Meh, a business can refuse to do business with someone for "reasons" except in regards to race in the US. Just like a certain cake maker in Colorado doesn't have to make me a wedding cake. AFAIK, Coinbase doesn't have undue influence on actually preventing miners from including transactions in blocks.
However, in EOS, the block producers definitely believe putting together blacklists is the way to go.
https://news.bitcoin.com/eos-decentralization-questioned-as-block-producers-freeze-accounts/WINNING
Fuck these KYC portals, we need better choices.
How widespread is it? I can't even read the fucking thing.