Also, satoshi nakamoto himself used the block chain in this "abusive" manner by embedding a message for the bankers in the first block. If satoshi didn't want the block chain to be used for other activities than purely monetary transactions then why on earth did he do it?
I think it was probably a pity that Satoshi actually did that (of course you know it was to show that there was no premine) as unfortunately his approach has been used by others and then extended through other approaches (I even worked out how to encode information in the sigs themselves although I've never actually used it live - come to think of it that is actually perhaps a better approach as it is just reducing the signature entropy a little and doesn't actually waste space).
It is inevitable that such pollution is going to happen and limiting dust is (at least for now) about the only reasonable method to preventing the UTXO set getting too large.
Using Bitcoin for other than monetary purpose is not abuse if you are willing to pay the price. (may it be either in fees or in dust)
You can't abuse Bitcoin anyway. Some tried, did not worked so much.