Weren't they the ones who pioneered DNS hijacking of unknown domains to serve their own recommendations and ads?
https://arstechnica.com/tech-policy/2009/08/comcasts-dns-red...
That's aside from all the political shenanigans they pull, trying to kill municipal broadband and net neutrality. There's scarcely a more evil ISP.
I switched away from Comcast as quickly as I could, and never had trouble with either smaller cable companies or fiber providers.