A Raspberry Pi can be trivially overloaded with a simple DOS attack. (Not even DDOS.) If you've got anything remotely controversial to say, I wouldn't count on that being sufficient to keep your site online. The infrastructure necessary to remain online during a coordinated attack isn't cheap; that's why Cloudflare advertises DDOS protection as one of the many services they offer:
https://www.cloudflare.com/ddos/Whether or not a cloud infrastructure company "owes" content-neutral treatment to their customers is a matter which, I think, is up for debate. Particularly in this day and age where the internet has become such an important venue for political speech.
