I am all for censorship resistant peer-to-peer electronic cash. That's what Bitcoin has always stood for; I don't understand why it can't stay this way and we have to expand to this all-encompassing 'censorship-resistant data storage + payments + social network' or whatever else people want to put on top of blockchain.
And I'm all in for that too, as long as the only disincentive to this is the transaction fee. I can't figure out another way to stop this upcoming junk without censoring. And if you have to censor certain transactions for not being in favor of "peer-to-peer electronic cash", you're opening the Pandora's box of "how do you know what's a currency transaction and what's not".
I already mentioned some examples how to disincentivize it. For instance, some privacy coins drastically reduce the amount of publicly viewable data per transaction due to encryption of many transaction components. Therefore, the overhead of misusing the blockchain for something it's not made for, becomes much more expensive, without having to resort to increasing the transaction fee
rate (as you suggest) which would affect everyone (especially also people just sending money around).