givingtago- M’dioraysa there are 5 spots that are problematic, and all others would be fine. Even in those 5 spots, the issue is only shaving (as opposed to uprooting) in a manner that destroys (as opposed to a scissors) i.e. a razor (????? ??? ?? ?????). Because we are unsure of the exact location, we refrain from shaving (with a razor) our entire beard (including moustache and neck). There is absolutely no Halachic problem with trimming (i.e. shortening the hair, not at skin level) any part of the beard, and certainly not the moustache. The only halachic problem arises when trimming close to the skin, with a razor. The dispute among the poskim is simply in regard to which modern devices are considered a Halachic razor.
When you talk about people “who wouldn’t touch their beards” i.e. not even to shorten with a scissors, that is not a Halachic issue, but one based on Minhag and Kabballah. There is thus a lot more leeway for allowing trimming of the moustache for various practical reasons.