Visibly worse versions of themselves, according to whose standards? Apparently the standards of someone who doesn’t use cannabis on any level, so thereby doesn’t really have the authority to determine whether his friends who are high are better off or worse off. I just can’t see anything other than someone making value judgements of their “friends”.
OP is clearly not upset about “personal choices” — they are sad to see their friends become visibly worse versions of themselves.
Expressing concern about troubling patterns of behavior is one of the greatest things a friend could do for me.