since i think continuing to discuss an ancient subject is pointless i redirect you to here: https://github.com/bitcoin/bitcoin/pull/3737
https://github.com/bitcoin/bitcoin/pull/3737#issuecomment-36383977
I agree with @gidgreen .
Words like "abuse" and "rape" aren't helpful. If you think the size of the blockchain is a big issue, then please help optimize it. Because even without OP_RETURN, the blockchain will get bigger. Forever.
BTW arbitrary data may be stored (and long and successfully saved) not only with OP_RETURN. I hope you heard something about "cryptografity"?
Moreover I can say that OP_RETURN is very impractical way for storing data in blockchain.
Much more effective is the using P2SH (or P2WSH) scripts like this
OP_DROP
OP_DROP
OP_TRUE
This is a more complex but with this way we can store over 1000 bytes in each output of standart transaction