Pronoun in English without specific referent

In German it can be used often and is not frowned upon in academic writing either.

I think this might be the issue here: not that your lecturers dislike the word 'one' per se, but they may be critical of assigning a position to an unknown or unspecified actor.

I seem to remember being pulled up on passive voice when in uni for a similar reason — it's appropriate usage (e.g. formal style), but if you say:

There is a belief that…

Well, who believes? Using 'one' has this same problem:

One believes that…

From experience, in the approach to humanities essays taken by UK(/Irish) universities, it's important to outline who in the field have put forward the points up to now & how you're putting these together to argue your point.

Arguments from a 'common sense' basis don't cut it :)

Usage of "one" as an unspecified referent is generally seen as pompous.

"One cannot help but seem rather stuck up when one uses one"

Informally "you" is commonly used:

You'll seem more normal using you

In academic writing a slightly more formal version is to use "we", meaning the writer and the reader combined:

We can all use we to sound slightly formal.

Note: Shamelessly stolen from @Henry's comment on the original question, but it needed to be made into an answer.

Your choices are:

1. one (seems pompous and affected)
2. we (the most common, can get overused or condescending)
3. the reader/('the student'/etc.) (stilted and overly academic)
4. you (unacceptable, way too colloquial)
5. alternatively, rewrite in the passive voice/infinitive/gerund/other noun phrase:

   'one can infer that X' -> 'it can be inferred that X'/'the inference that X can be made'/'inferring X, we conclude that Y...'

Personally I prefer 5. over 2., it flows better and it's less obtrusive; 2. however is more common in academia. If you must use 2., my advice is to mix it with 5. Whatever pronoun you use to address the reader, too many of them gets annoying and distracts from the narrative you're trying to set forth; it feels too conversational.