Would it be possible to consider them separately though? Like maybe it will turn out that say 10% of them are beneficial, 65% of them are neutral (either they do nothing at all or a mixture of benefit and harm), and 25% are slightly bad for us (can't be too harmful or we would have already known ig).
Delivering gene therapies into brain cells is a non-trivial task. Also, there's alternatives to cutting the original sequence out; you can also dampen the transcribed RNA with downstream therapies.
'Bad' is notoriously hard to figure out. It might be good for the group to have a few people with major psychiatric disorders even if it's not ideal for that individual or the people who have to directly interact with them.