Your account was registered in February of this year and somehow you've gotten so concerned with forum politics that you're asking why a single account didn't get tagged way back in 2016?  Yeah, I'm sure you're not an alt account of one of the troll posse members.

To answer the question: I have no fucking clue why I didn't tag him back then.  Maybe I didn't notice it.  Maybe I removed the tag, which I tend to do for members who've shown themselves to be trustworthy over time.  Don't remember, and at this point I don't care.  I'm not going to tag anybody in 2019 for an account sale in 2016. 

That's the only response you're going to get from me, so if that satisfies your question (or not), you can now lock the thread.