Is "Anonymous" actually a gang? Does a large group of people from around the world use the channels (4chan.org, 8kun.top, and the other chans) to commit all varieties of crimes, together, as a group, all around the world?
You associated with any crimes committed by users of these sites? Guilty as one who should be a primary suspect, or as an accessory, to any crimes associated with these sites?
The assumption is that they might claim themselves to be "Anonymous", a member of "Anonymous". This of course is in reference to being named as "Anonymous" automatically upon posting on sites such as these.
That a person claims to be a member of Anonymous does not necessitate that they are involved in any crime ever. Some may sooner belong to another faction, or other factions, of Anonymous, which isn't so much a gang.
Some of Anonymous would be in a gang, or there are multiple gangs within Anonymous that can simply be called "Anonymous". Some Anonymous are actually activists, lawful ones, who are not in a gang. Some Anonymous are simply users of at least one channel website that uses the automatic "Anonymous" feature, which is the automatic title/"name" of "Anonymous" being the one given to a poster upon posting. Such as this post here.
It's not wrong, I feel, to claim that members and factions of Anonymous belong to a terrorist group or to terrorist groups. That factions of Anonymous are terrorists and war criminals. That crimes that would qualify as such have been carried out by Anonymous, terrorism and war crimes.
Some members of the criminal factions of Anonymous are very involved with many crimes, past and present.