That's only because nobody's gone after an ISP for the same kinds of things that they go after Google for, with respect to the stupid Section 230 changes. When the outrage mob discovers it can bully an ISP into shutting off political opponents, then the ISPs will be exactly like Google, Facebook, Twitter, etc. You already see echoes of this for example with Jeff Atwood's misfire on Twitter recently, going after Azure because he thought Gab was still being hosted there (it wasn't)[0]. Incidentally this is one reason why Section 230 was so important. The change is new, so it's probably just a matter of time before the outrage mob starts going after the T-Mobile and Comcast accounts of its enemies.
[0] https://twitter.com/codinghorror/status/1056426165274009600