Anyone can do all sorts of things. I can punch anyone I see on the street in the face. Doesn't mean they're actually doing it.

Now, I have a vested interest in this as I work on one of those tracking tools, but it actually collects less data than those Apache access_logs that people have been keeping for 25 years. Plus, the JS is unminified and easily examinable if you want (as is the HTTP request), so you also have more insight in what is being collected exactly.

"It's using JavaScript" and "it can do [..]" are massive red herrings; browsers are actually fairly sandboxed and there are millions upon millions of lines of code on your computer that can do much more than JavaScript inside a webpage.