Flare, It's 100% not okay for you to pick a fight for ANY reason, especially as a moderator.
Some of the comments you've thrown are unprofessional and very rude.

Hating on someone for using drugs is pointless.
It's their decision and if they're fine with it, that's it.
If you cannot be around someone without making nasty comments in every post, don't talk to them.

And ya'll need to stop his bullshit before everyone gets mad and it'll be very awkward.