Saying good game or similar at the end of a match is a tradition that predates both league and the Internet. Offline it also involves lining up for handshakes. Obviously traditions and words meanings change with time, but I don't think we are there yet.
If it helps it's about respecting the game more than any individual match or player, and if you don't feel that way about your game it's probably time to reevaluate if you should take a break or move on. People should spend their free time doing things they love, I think.
"Thx for playing" may work?