Shadowbans , are probably the reason behind this, once you get shadow banned it’s next to impossible to use another acc, without them banning you immediately, the only way to use it if you have a different, device, IP and browser to evade their detection. As opposed to actual sitewide bans, that they still allow you to use another account, provided you don’t interact with the sub you were banned in.

The purges this time around were different, they were just linking accounts and banning them all at once now. Also from another forum, I read they got better at detecting the methods that they were using to evade bans.