[heinrich5991]

It's hard to host a website if you don't have the support of CloudFlare or something similar, DoS attacks get you off hosting providers pretty quickly.

[jamespo]

Not only are the alternatives to CF as you acknowledge but the number of sites hit by DOS attacks is low in the grand scheme of things.

[nitrogen]

The sites most in need of free speech protection probably also need more DoS protection (see DoSes of GitHub, for example).