Content neutrality is a higher bar than you think it is. Content-neutral means the rules cannot take content into account at all.
If the content is millions of ssh login requests on thousands of servers with ec2-user and the top 10000 most used passwords, the infrastructure should be able to block that.
Content-neutrality would probably make it illegal to prevent DDoS attacks. At some levels of infrastructure, sure, but broadly speaking, content-neutrality seems like a bad requirement.
Viewpoint-neutral, however, is a better goal.
https://www.law.cornell.edu/constitution-conan/amendment-1/o...