But IMO bitcointalk have more rules (compared with other forum) with more strict moderation, which is turn off for users who want to have casual discussion/question.
Dunno, my experience so far across dozens of forums in the last ~20 years has been pretty much opposite, with bitcointalk being far less strict than any other forum I ever visited.
The only thing that maybe gives impression of bitcointalk being strict is plagiarism rule, but even with that you are far less likely to get banned here than anywhere else.