The noun for when no individual in a community is doing wrong but the net result of those actions is evil?

I hope this question is legitimate under the strict rules of this forum?

It is possible that the accumulated effect of a number of good people’s actions can be evil, not just in a discrete situation, but as the result of a change of one social more without awareness of its consequential effect? Is there a word for this?

Solution 1:

A few terms come to mind, though they do not follow your definition precisely:

• Tragedy of the Commons - the idea that when individuals share a common resource, they end up acting contrary to the common good.
• Diffusion of Responsibility - the idea that people are not responsible for the outcome of their actions because the outcome is the collective result of multiple people's actions.
• Little Eichmanns - these are the individuals who are doing actions that are not evil per se, but contribute to evil by being complicit in a larger evil system.
• The Banality of Evil - describes the phenomenon of the "Little Eichmanns".

Solution 2:

A very general analytic term for this is the "horizon effect" or "horizon problem".

Wikipedia does a decent job explaining the origins and use of the term, so I'll go ahead and quote it -

The horizon effect, also known as the horizon problem, is a problem in artificial intelligence where, in many games, the number of possible states or positions is immense and computers can only feasibly search a small portion of it, typically a few plies down the game tree. Thus, for a computer searching only five plies, there is a possibility that it will make a detrimental move, but the effect is not visible because the computer does not search to the depth of the error (i.e. beyond its "horizon").

When evaluating a large game tree using techniques such as minimax with alpha-beta pruning, search depth is limited for feasibility reasons. However, evaluating a partial tree may give a misleading result. When a significant change exists just over the horizon of the search depth, the computational device falls victim to the horizon effect.

Hans Berliner named this phenomenon in 1973, "The Horizon Effect",[1] which he and other researchers had observed. He split the effect into two, the Negative Horizon Effect is when it "results in creating diversions which ineffectively delay an unavoidable consequence or make an unachievable one appear achievable." For the "largely overlooked" Positive Horizon Effect, "the program grabs much too soon at a consequence that can be imposed on an opponent at leisure, frequently in a more effective form."

The term is now applied freely to matters where the horizon takes very different forms than in the original use. It this case, the horizon may be time scales, where the full accounting of the effects over time is not realized. Or it may be spacial, where the full span of the effected area is not taken into account. Or it may be due to a non-egalitarian approach to weighting values which causes the score to change depending on your perspective. Often, the closer you are to some local optima, the less likely you are to find the global optimum.

CEO Horizon, Optimal Pay Duration and the Escalation of Short-Termism∗
Ivan Marinovic† Felipe Varas‡, June 12, 2017
Abstract
This paper studies optimal CEO contracts when managers can manipulate their performance measure, sometimes at the expense of firm value. Optimal contracts defer compensation. The manager’s incentives vest over time at an increasing rate and compensation becomes increasingly sensitive to short-term performance. This process generates an endogenous CEO horizon problem whereby managers intensify performance manipulation in the final years in office. Contracts are designed to foster effort while minimizing the adverse effects of manipulation. We characterize the optimal mix of short and long-term compensation along the manager’s tenure, the optimal vesting period of incentive pay, and the resulting dynamics of managerial short-termism over the CEO’s tenure.

While this example happens to involve an exploitative situation (it's based on the assumption that the manager will exploit the situation), It's intended to show the free use of the term outside of game algorithms in ordinary writing.

Another technical, model related paper, but far distant from the game engine origin.

The investment horizon problem: A resolution
Knut K. Aase ∗
Abstract
In the canonical model of investments, the optimal fractions in the risky assets do not depend on the time horizon. This is against empirical evidence, and against the typical recommendations of portfolio managers. We demonstrate that if the intertemporal coefficient of relative risk aversion is allowed to depend on time, or the age of the investor, the investment horizon problem can be resolved.

finally, a very generic and relevant example.

Horizon Effects, Sustainability, Education and Ethics: Toward an Economics of Foresight
Frederic B. Jennings, Jr., Ph.D. 22 June 2007
Abstract: Horizon Effects, Sustainability, Education and Ethics
The core of an ecological economics is interdependence: substitution and complementarity. Yet orthodox economics stands on substitution assumptions as the universal human relation. A theory so founded does not apply to a complementary realm. The optimal organizational form in a world of substitution is competition among our resources. Where complementarity rules, however, this is precisely wrong: cooperation is sought instead. Interdependence is also the basis for bounded rationality theories. If consequences sweep outward forever, our prior anticipation of those outcomes shall be contained. The range of our understanding – called the planning horizon in choice – sets the boundedness of our rationality into an ordinal frame. Especially in the presence of complementarity, impacts grow as they spread, displacing competition for cooperation as our welfare ideal. Examples are found in ecology, education and ethical culture: none are well served by competition. The health of ecology lies in complementarities sundered by competition. The educational system in its intangible information may be our clearest case of complementarity: it is a good illustration of failure. The ethical manifestation of this problem is short horizons, a culture ruled by myopic concerns. Such conclusions are framed within a horizonal theory of foresight, to be explained below. Prices, economic growth and most of our ecological losses are tied to planning horizons, which extend through learning and trust. Longer planning horizons transform substitutes into complements, a shift of interdependence calling for institutional change. Without adapting incentives to cooperation, progress is slowed: horizon effects show why. A horizonal economics of complementarity is introduced and discussed. KEYWORDS interdependence, complementarity, cooperation, planning horizon, conscience, ecology, economics, education, ethics 1 This paper was presented at the INFER 2006 Workshop on “Bounded Rationality in Economics and Finance” in Loughborough, Englan d.