Okay, I asked Meta AI why:

The term "doxxed" is a verb that comes from the word "dox", which is a shortened form of "documents". The "x" in "dox" is a nod to the hacker culture and the practice of digging up and revealing personal information online.

The reason it's "doxxed" and not "doxed" is because of a linguistic phenomenon called "pluralization" or "verbification". When a noun becomes a verb, it often gets a double consonant or a changed spelling to distinguish it from the original noun.

In this case, the verb "doxx" (to reveal personal info) got a double "x" to differentiate it from the noun "dox" (documents). Then, when the verb "doxx" is converted to its past tense, it becomes "doxxed".

So, to summarize:

This might seem weird, but it's a common pattern in language evolution!