What is another word for a reason that is "not the real reason"?

The real reason is what you get if you go a couple of levels deep. Why do you do go to work? Because I have a job. But why? Because I need to make money. But why? Because we live in a capitalist society where goods and services are exchanged by money and I can get money by helping somebody else achieve their goal.

So how can I describe the first two reasons: superficial, smoke-screen, non-real?

Solution 1:

From Wikipedia:

A proximate cause is an event which is closest to, or immediately responsible for causing, some observed result. This exists in contrast to a higher-level ultimate cause (or distal cause) which is usually thought of as the "real" reason something occurred.

Solution 2:

If the reason offered is a plausible fake, with bad intent, then you're talking about a pretext.

pretext: a purpose or motive alleged or an appearance assumed in order to cloak the real intention or state of affairs
https://www.merriam-webster.com/dictionary/pretext

If, as the example in your post implies, the reason given is just simpler or easier to understand, then I think you probably can't outdo superficial reason as describing exactly what you're talking about.

There is also putative reason, but a putative reason is a pretext.