Yes, that's pretty much the definition of doxxing. And then publishing it in a public forum for everyone to see.

What did you think it was? Anything else would typically be illegal illegal.

Pretty much anyone's (in the US at least) information is relatively public. This includes addresses, phone numbers, real estate transactions, criminal records, and far more. Most things people think of as private simply are not.

Hence why doxxing is against ToS for most platforms.

Actually, yes, it is. Not trying to say anything on the topic of doxxing billionaires vs. doxxing a member of the masses but, as a member of said masses, I understand that my social security number, home address, name, and date of birth, to name a few, are publicly available information. Aggregating that information on some forum is literally what people call doxxing.