The GT fanbase probably ties the Forza Horizon Fanbase in terms of retardation.
The GT fanbase is terminally stuck in the past, sucks at their own games, is horrendous at processing information, and lacks the ability to have any form of higher discussion out side of "I like this car! Really? I Like this car too!" They also think that GT is some niche, Japanese car culture racing game just for them despite it being a mass market AAA title, and they will actively fight anyone who suggests any feature from old games was bad or could have used work.
The Forza Fanbase is largely the fortnite fanbase, which is their target audience. It caters to internet car culture and kids who like youtubers and stuff.
NFS is a bunch of spergy JDM/drift kiddies, similar to the GT fanbase but not as bad.
The crew 2 is really hit or miss. Tons of fucking arabs playing the game, but theres a big core community of hobbyists that are actually pretty chill. Big update for that soon.
Bith the Forza Fanbase and GT fanbase could genuinely be their own cows. The shit flinging and retardation from both sides is fucking insane, and it extends beyond reddit.