No one claims there is a requirement to grow a beard, though as a matter of fashion almost all Hasidim (and most frum Jews) wear one. After all, most men were created by Ha-Shem with beards, and who are we to question His judgement. Maybe the more modern do, but Hasidim are happy to do things the way Ha-Shem wants, that’s what defines being a hasid – and it is obviously Ha-Shem wants beards.
There are halachic issues on shaving and cutting hair, but no one requires growing a beard. If for some reason you can’t grow a beard, you can’t grow a beard.