A bit of that, and the fact Avast got caught just a few years ago massively spying on all their users and selling their data both in their browser extension and free anti-virus apps.

This is a fair question. Everyone is piling on here, sort of without regard to whether anything bad has actually happened. Of course, even if they don't change anything, the extension is now funneling whatever data it collected to Avast, a company that many hold in low regard (myself included). But it would be appropriate to have a discussion about what they're doing now that's bad, aside from not telling anyone about the acquisition.