If you make it so ilvl > transmog roll, all the high level moggers don’t bother with lfr, the raid is much harder, and everyone else in there with you actually does need the item. Either way your chances of winning loot are the same (probably lower actually because the mog people won’t roll for things like jewelry or trinkets), it just takes longer.
I personally stay out of lfr because I’d only be going for mog, but I don’t nitpick when it comes to who wins what for which reason. You were both there, you both contributed, you both get a fair shot at loot. Why should the other player be punished because they put in more work than you beforehand?