Call it stalking or harrasment if you prefer. Regardless its rude (sometimes illegal) behaviour.

That's no justification for using visitors to your site to do a DDOS.

In the slang of reddit: ESH

It's neither of those. Stalking refers to persistent, unwanted, one-sided interactions with a person such as following, surveilling, calling, or sending messages or gifts. Investigating a person's past or identity doesn't involve any interaction with the physical person. Harassment is persistent attempts to interact with someone after having been asked to stop. Again, an investigation doesn't require any form of interaction.

> Harassment is persistent attempts to interact with someone

No, harassment also includes persistent attempts to cause someone grief, whether or not they involve direct interactions with that person.

From Wikipedia:

> Harassment covers a wide range of behaviors of an offensive nature. It is commonly understood as behavior that demeans, humiliates, and intimidates a person.

Doxing in the loose sense could be harassment in certain circumstances, such as if you broadcast a person's home address to an audience with the intent to cause that audience to use that address, even if the address was already out there. In that case, the problem is not the release of information, but the intent you're communicating with the release. It would be the same if you told that audience "you know guys? It's not very difficult to find jdoe's home address if you google his name. I'm not saying anything, I'm just saying." Merely de-pseudonymizing a screen name may or may not be harassment. Divulging that jdoe's real name is John Doe would not have the same implications as if his name was, say, Keanu Reeves.

Because the two are distinct, one can't simply replace "doxing" with "harassment".

Generally speaking, every case I've seen of people using the term "doxing" tends to be for the case that specifically is harassment; it has the connotation of using the information, precisely because if you aren't intending to use it there's no good reason for you to have it.

That's just another way the term is used incorrectly.

Language evolves. Connotation tends to become definition. Not always the only definition, but connotation becomes the "especially" or the "definition 2", and can become the primary definition over time.