Alright, while the this flair does sometimes brings forth nice content, it is a very rare occasion. 9 times out of 10 it will just be part of some 9 year old's minecraft letsplay. Scrolling through this reddit for a bit, I found such posts disturbingly common. You've probably encountered such things before at least once, and what's worse is that since it isn't exactly against the rules to post such things, the people who do post them post the same thing again and again and again. Comments that discourage them from doing this and downvotes on their posts usually have little to no effect. This is most likely because well…they're kids, do you expect them to understand logic like that? Anyway, I feel that there seems to be only one solution to this: Posting letsplays is now against the subreddit rules and doing so will make your post viable to be deleted. Perhaps a bot can also be implemented to delete posts with common letsplay names like "ep 1" or "watch this". Of course, to faciliate this change the letsplay flair would also have to be removed.
But hey, that's just my opinion. Feel free to criticize in the comments.

The infernal noise they make when you get into a fight with them legitimately scares me…