This same thing exists in Bitcoin, which is why Ordinals use witness data instead of OP_RETURN.

You can think of Monero's tx_extra as being similar to OP_RETURN and having similar caps in size.

There is no reasonable way to prevent arbitrary data storage on-chain through steganography, it has to be possible for other "real" use cases to work.

The only real pain is that they don't pay full fees due to segwit discount, other than that it is what it is.