If I set up an 18-hole game, I need to know that all the players will complete it.
If you show up with your "poor" ratio, I'm going to instantly boot you out - because it's likely you'll ruin the whole game by quitting at some point, wasting everybody's time.
Furthermore, I have no sympathy on the "people play too slowly" thing - it says right on the selection screen what the time limit is. If it's 90 seconds, then you should expect your opponent to spend all of that time on every shot. That is their right; if they go over 4 times during the round, they get disqualified. The game itself has sanctions for slow play.
If you want a faster game, select 45 or 30 seconds in your filter before you look for a game. Then you're guaranteed of fast play,
My own hunch is that you're being booted for having a poor completion ratio, and deservedly so. That's why the host should be allowed to boot anyone they want as often as they want until they get the sort of reliable players they want on the selection screen.