Neocities does not allow you to run any code, just static html serving
Actually, that applies to any server, (web)hosting, datacenter rack, internet connection, bank account, domain name. As soon as your provider (or the powers that be) notices you, for example a complaint or a government official email, they will take down your hosted system or connection. In 45 year of internet and datacenters I never ever saw an exception to this rule. Even Tor hidden servers are taken down.