But how do we balance that with Bitcoin’s neutrality?
Where’s the line between protecting the protocol and restricting usage?

Data storage was always considered an abuse of Bitcoin.
https://en.bitcoin.it/wiki/Spam_transactions
https://en.bitcoin.it/wiki/Weaknesses#Illegal_content_in_the_block_chain
https://gnusha.org/pi/bitcoindev/CAAS2fgSkiqfhJxHJNw8i8G5yd1XY6tUTDynQ+AekbwmHP_jZmw@mail.gmail.com/t/#u