The user created a plausibly valid tag (on another user's question).
By that time it was clear from all the released material that Kylo Ren is a major character. I shall avoid posting 3-page-long bullet list of why, to avoid spoiling people.
While there may be valid arguments made on the side of the tag not being valid[3], there are very valid arguments on the side of it being valid, and therefore NOT unanimously and unchallengingly worth-deleting without debate and discussion. This Q&A is not the correct place to settle that argument, but what's important to what happened is the fact that it's a meaningful disagreement on merits, not a unanimous and obvious "junk" tag conclusion.
The tag was challenged without knowing this fact, and without checking this fact (e.g. on main site or Meta), and deleted by a moderator without seeking the site consensus on Meta, as is appropriate for tag deletion
As per the challenger, the basis of the challenge was 2-fold: (#1) he considered the tag invalid (as per above, I greatly disagree with him on merits of that judgement call, but it's his right to make that judgement call); and (#2) considered it inapplicable to THAT specific question (another judgement call, that I am ambivalent about, I can see valid reasoning to either support or oppose that call on merits, and think it was far more correct than #1).
As per comments from moderator, the FORMER basis of the challenge (validity of the tag itself) was the basis for fulfilling the flag. As such, I believe it necessitated a Meta discussion prior to deletion and should have been rejected until such Meta discussion was resolved. (For hypothetical completeness - I may have arrived at the opposite conclusion regarding moderator's action if the reason for the deletion was the second basis of the flag - question content, including tags, is definitely within moderator purview and ordinarily wouldn't need to be Meta-discussed. I may have disagreed with moderator's judgement but NOT his procedure then.)
Regardless of the intentions of the action, the practical - if unintended - effect of this action was that the user was deprived of an official, SE-promoted, activity (creating new good tag) - and as a consequence of that:
- ##user lost a chance to earn a rare badge awarded for creating a tag that is used by 50+ questions[1]
user lost a chance to earn a rare badge awarded for creating a tag that is used by 50+ questions[1]
- ##user lost a chance to earn a rare badge awarded for creating a tag that is used by 50+ questions[1]
This was compounded when - according to the OP, his OTHER 2 tries to create the tag were also rejected. I do not possess the knowledge of how to dig through the data to verify that, or to see the circumstances, except that I know that OTHER people were involved than the user who challenged the tag's first instance - so this is a pattern of events that transcends a single user's one judgement call.
Then, to add insult to injury, someone else created that tag and will get the badge that the OP was deprived of.