I generally support 230. There may be some tweaks that could be made that I would support, but the general concept behind 230 is correct.
> Are private entities responsible for the content they host?
Generally no. Private entities are responsible for the content that they publish, not for the content that they host. An example being the comment section on a news site versus the news article on a news site. The latter is content that they published, the former is content that they host.
> If we repeal 230 and someone posts something falsely defaming me, who do I sue?
IANAL but I would imagine if 230 is repealed and some one libels you, you sue the platform and the content creator.
If 230 isn't repealed you sue the content creator and ask for an injunction against the platform to remove the content.