Revealing publicly available information (actually publicly available, in the sense of "any person can easily look this up", not "publicly available" in a sense of "publicly available in leaked databases", which actual doxxers use as an excuse for their actions) isn't doxxing.
ಠ_ಠ
Doxxing has never been restricted to just leaked databases. I'd argue that any publishing of personal information in a context in which the individual clearly doesn't want to be identified counts.
The owner of the site is not identified anywhere on the site itself. And I think we can both agree that it's the sort of site whose owner would prefer to remain as anonymous as possible. The blog post digs up information about the owner from whois records, which do count as easily accessible public information, but then links to Kiwifarms of all places, and goes on to talk about identifying writing patterns and doing "detective work" involving cross-referencing profile pictures of accounts on various websites that were obviously not intentionally linked together by their owner. This is a textbook doxxing attempt.