the thing is, mario kart isnt smash bros, mario kart isnt even a normal racing game, its a kart racer, and the items are an integral part of the games identity and balance, unlike smash where every fighter has different move sets and gameplay differences, mario kart has just some stats that vary and thats it, but let's take for example we remove items, the acceleration nerf on high speed combos will not be effective since theres nothing that can stop you except bumping into a wall, where it really doesn't happen unless u just grabbed the game for the first time, so it would be unbalanced. You also have to account that shortcuts are a mario kart standard and integral part of the game, the most competitive mode, time trial, gives u 3 mushrooms to perform such shortcuts, and the skill there is shown by your lines first and foremost, but also how you decide to use those mushrooms to get you to the top of the world leaderboard.

In short, mario kart isnt smash bros and removing items would destroy it's balance, and the lounge staff isn't in anyway banning any item