Such transaction would be deemed non-standard though since the standard enforce only 1 OP_RETURN with maximum size 80 bytes per transaction. And while people can split X OP_RETURN output to X transaction, there are big overhead which supposed to discourage people from adding tons of arbitrary data.
right. so people saying that bitcoin shouldn't be used to store data well, that capability has always existed. what those people really must have an issue with is if their fees go higher. that's what they're really complaining about...because they never complained about op-return.

Not really, OP_RETURN added about when Bitcoin Core 0.9 released[1]. It seems the main goal was to remove incentive from abusing address to store arbitrary data (which bloat UTXO) rather than facilitate people to store arbitrary data. Although i agree people's main issue actually is about high fees. Imagine what kind of complain we see if someone decide to make BRC-20
clone (which use OP_RETURN rather than Taproot witness data) and suddenly become popular.
[1]
https://bitcoin.org/en/release/v0.9.0#opreturn-and-data-in-the-block-chain