I'm sorry but I disagree, it doesn't matter if it's here or if it's in another game. Immersion breaks will always be a thing and I personally have yet to find and play a single MMO where something in the game exists that doesn't break immersion for someone. It's fine though and as long as people are enjoying whatever it is then who am I to pass judgment on the mount, glamor, or whatever it is they find fun. It's totally okay to break away from the seriousness for a little to just have some silly fun. Of all the things to complain about in any game immersion breaks are far low on my list.

As for the Call of Duty thing....you'd be surprised. When World of Warships did their April Fools event and released a map that was a bathtub and players were driving toy boats. Players raved about it and wanted the map to stay in it year round I remember my friend telling me.

It's okay to have a sense of humor and it's okay to let other players enjoy something and be happy even if it's not something you enjoy.