It [Opt-in RBF] reduces the functionality of zero confirmation transactions.
Good! zero-conf was the definition of stupid when I got interested in Bitcoin, and with good reason. It's not Bitcoin's fault if later arrivals ignorantly tried to hammer a square peg into a round hole. (Gavin can take a lot of credit for this mis-hap due to his chronic mis-management which, as best I can tell, was at first out of ignorance and later out of malice.)
If I am a merchant should I reject RBF? Since if I did do this could cause other problems as well. Since it is the person that sends the transactions that chooses to opt in not the receiver.
Transfer your Bitcoin (in the unlikely event that you have any) to a wallet service which guarantees not to do RBF then and let them interact with vendors. Or just use ACH/PayPal if you like it so much. Many of the rest of use have use for something different.
You claiming that this is not a contentious issue is obviously not true considering the noise that is presently being made on reddit even with all of the censorship.
You are welcome to move onward and upward to redditcoin at your earliest convenience. Don't let the door hit you on the way out.