Why do you speak of it as decided that data storage in the Blockchain constitutes abuse?
It's abuse because you're
forcing others to download/store your data against their free choice.
Every full node must download the full blockchain (prunable or not!).
Every full node has consented to download and store
financial transactions.
NOT every full node has consented to store anything else.
You need 100% consensus for this, not merely some subset (ie, not miners; not developers) or even a majority.
Furthermore, everyone is free to store data that isn't in the blockchain.
There is nothing to be gained by putting it in the blockchain
except that you force it on those who don't want it.
Explain how this is anything
but abuse...
First of all, Counterparty transactions
are financial transactions.
Second, every full node has consented to download and store
the Bitcoin blockchain, no less. That is, transactions that accord to the Bitcoin protocol, which Counterparty transactions obviously do. Satoshi imbedded a political message in the Genesis Block, for Christ's sake... You have a much narrower view of the possible use cases for Bitcoin than do others. (See what Peter Todd wrote above.)
By your reasoning,
Bitcoin should never be used for anything new, ever.