It is worth it to refund it to send the message. We have seen what happens with ubisoft when they just stop supporting a game. What is stopping Sony from discontinuing matchmaking down the line after forcing a psn account, thats in addition to the regional restrictions and the fact they leak like a sieve.
Helldivers 3 could come out and they decide to just stop access to 2.
Money is the only thing these execs care about. Its worth tanking a game so they get the message.