Looking at the site I suspect someone doesn't agree with free speech - common misconception in the US that free speech only applies to stuff you agree with.

Wherever you host next try fronting with Cloudflare and make sure your origin servers only accept connections from their servers. Cloudflare generally supports free speech and it provides a layer of indirection to keep people from complaining to your hosting provider. Make sure you don't expose your origin IPs in server messages or DNS.