Yes, there are laws against doxxing in several countries.

There is no technical aspect stopping it. Every website has your IP, sometimes also the people you chat with or write emails to, as this might (or might not) be part of the meta-information.

An IP address is a boring piece of information. Usually you can just infer the country and which internet service provider someone uses. You'd need to sue the ISP or get a court order to get the name and address of who's using that IP number.

Running these services is a lot of work and requires some skill, at least to do it sustainably. Usually it's certain people who are dedicated enough and willing to put in the effort... They are motivated to build something or help people. That's what drives them. It's somewhat unlikely but not impossible that they participate in malicious behaviour. Sometimes internet drama happens. But users aren't stupid either.

(But people who want to destroy and troll, rarely have the character traits to succeed at something like this. You'd pass on easier methods to wreak more havoc, to instead spend time learning webhosting, Linux, build up a community and maintain the server... You wouldn't do all of that unless it were worth it. I can only imagine that happening in a targeted attack that pays a good amount of money. Or a really good amount of internet fame because you doxxed a high-profile celebrity or something like that.)