They have abused wife syndrome. They know they are being hurt, lied to, abused and more will follow. Because it is familiar to them, they stay loyal to the party ever hopeful they will be rewarded and treated better. Nothing changes for them. You see it here daily, we both do. We can make a meme already knowing which troll will show up, which debunked dim talking points they will use and at what point they will switch to using an alt account to bolster the debunking lies.
Over the years we have seen more and more walk away, the numbers of trolls have fallen low enough the alt accounts are needed.