Illegal drugs are bad and there is no place for them here!! I agree.
Drug related usernames

I think the point is that they, along with some other user names that are offensive for other reasons, are not appropriate here as per the site's Rules:
Keep It Clean
You may not post any offensive content on Chess.com including your username, avatar, or personal description. You may not add any offensive comments, chat, or other content. The following behavior is prohibited and can result in your being kicked or banned: cheating, using offensive/vulgar language, using toilet humor, making personal attacks, spamming or advertising competitive websites, religious or political debate, intentionally pointless/distracting posts, and discussion of illegal activities (drugs, etc).
(emphasis mine)
I think the appropriate course of action is to use the Report Abuse link that is at the bottom of each page.

Offensive in general -- use your best judgement when deciding whether it needs to be reported or not and let chess.com make the final call.
"Discussion of illegal activites (drugs, etc.)" is clearly stated to be against the Terms of Service here at chess.com, yet many users are permitted to maintain accounts with drug related usernames.
Today I witnessed a member who's comment vanished from the chat room when they typed "Kasparov [does drug X]", yet the chat room had no less than three active members who's usernames directly reference that same drug.
I have asked moderators about this inconsistency, so I can better understand the rules and know what I am and am not allowed to discuss without breaking them, but I have received no clear answer. It was suggested that I contact Erik directly, but I am uncomfortable with that because his profile page asks not to message him with abuse reports or "Site issues".
So I'll start this forum thread for members, moderators, and maybe Erik to discuss and clear up this issue. Please try to keep to thread related to the rules about discussing drugs, without actually discussing any drugs; I don't want the thread to be locked up.