It happened with us 2 seasons ago against Fenix and was a key factor which cost us a playoff run.
I went against the rules and closed down the room immediately after the race which I was told I did NOT have to do. MKU staff in chat told me to stop and continue racing when you all decided to quit an ongoing match. Being nice, I wanted to reset the lobby for you.
If you're upset I would consult MKU staff but they will tell you that it's a necessary rule. But keep in mind, 11 other races played into the end result. And I didn't want to take a free top 6 on RWS. I couldn't run up the score more with my good conscience despite your whole team leaving the lobby on or prior to race 7. We reset the lobby which I did on my own volition against the suggested rules.
But I would prefer if you refrain publicly bashing the team which had no say into how the league runs its rules. I also think being DMed privately being called other nasty words is unnecessary too. It's a crappy rule but it's necessary. I've been on the other side on it. But it's clear I extended an olive branch here to keep you guys relevant in this match up.
If it's any consolation, out of conference matchups happen once per season.
As Ice-T famously said: "Don't hate the player, hate the game".