and, if somebody harms themselves, does that give you the right to harm them too? does that undo the whole thing?

well, if somebody punches themselves in the face, does that mean it's ok to join in?

if somebody stabs themselves, does that mean it's permissible to stab them?

i think very few people would suggest that.

likewise, my failures around tobacco don't mean it's ok to blow smoke on me when i'm not relapsing, and it doesn't take a lot of depth of thought to realize that.