Community events are items that show up in the "community bulletin" section of the front page. Sites use these to announce everything from upcoming space launches (Space) to new blog posts (SciFi, Worldbuilding, maybe others). They have nothing to do with people getting together. I just added a wiki excerpt for community-events.
The "events" tag has a mix of questions (some probably mistagged). Some of them ask about chat events, which are like scheduled "meetings" in chat rooms. These, too, are not about offline activity.
"Meetups" seems to be about offline gatherings.
All three tags are relevant, though "events" should be reviewed. If all the questions that should have this tag (a subset of the ones that do) are about chat events, the tag should be renamed chat-events for clarity. (Update: apparently there is a chat-event tag already, so we can retag these.)
conferences has three questions, two of which are about specific conferences that happened in the past. I suggest retagging these with meetups.