They aren't removing 2D clothing, but they're increasing the price to upload and sell 2D clothing. They were originally planning to increase the price to upload 2D clothing up to 200 Robux and increase the price to sell 2D clothing up to 600 Robux.
Roblox got so much backlash from this that they are instead making the price to upload 2D clothing 80 Robux instead of 200 Robux (idk about selling them tho). They are also lowering the amount of Robux you get from a 2d clothing sale from 70% to 30% (So if you were to sell a 2D shirt for 10 Robux, you would only get 3 Robux when someone buys it).
My theory is that Roblox's plan is to make 2D clothing so unprofitable that we just stop making them. So they can remove it in the future and point fingers at us while saying "You weren't making 2D clothing so we removed it."