Having done that quite a bit yourself, Strudog, I'm amazed to see you kick poll someone else for doing it.
Since the kick poll wasn't based on a good reason, rejoining for the round is not a big deal. The reason why rejoining is forbidden in the first place is to give a player two lives in one round by abusing the system (spawn-rape enemy, die, rejoin etc.).
I'll let this slip this time, but don't kick poll without a proper reason anymore. I understand your frustration on HX/HA with no chance of winning dragging the round out, but the rules states that they're allowed to stay on their horse as long as there's enemies to hit. Flags will always pop up, and if there's a map where you can hide away from the HA/HX at the end, he must dismount. As long as the rules are as they are, you'll have to follow them.
Consider this a warning.