The question Which scientists (mathematicians, philosophers) who voluntarily served Nazi had large contributions to human knowledge? seems like it is requiring a list of notable Nazi scientists (the question also seems opinion-based) - my question is, do we allow big list questions or put them on hold (for being at least 'too broad'), with the advice for the questioner to refine the topic?
To formalize the comments, yes, big list questions should be put on hold. They really don't work with this format at all. They are especially problematic in the definition stages of private and public Beta. We are trying to recruit real experts in the history of science. Big list questions attract more pop-history answers, and will not attracts the experts we want/need. If we ask a lot of big list questions during Beta, we will continue to get a lot of big list questions for the lifetime of the site.
That particular question could be narrowed by asking about specific scientists. Heisenberg, for example, is particularly controversial. Mengele is known to have carried out experiments we now regard as inhumane; what was his thought process at the time? And so on. I suspect that any big list question we would want to keep could be narrowed to specific examples in a similar fashion.
I disagree. First of all, on other SE sites, list questions are not put on hold automatically just because they are list questions. For example on MO, which among SE sites has the largest proportion of professionals. They even have a special tag for list questions. And some lists are very interesting and useful.
Just out of curiosity, go to MO, click on Tags, and type "big-list". You will see quite a few interesting and useful list questions.
I agree that the list question cited in this question is not a good one. But there are also interesting list questions, to which reasonable answers can be given, like this one, for example:
Speaking of pop-history answers and questions, there are indeed too many of them on this site, and I see very few questions which could be asked by "experts in history of science". Also from the vote statistics, I can conclude that there are really very few people here who appreciate serious history of science, while pop-history questions and answers get many votes.
But I don't think that the reason for this is in the "list questions".