I get why some want to play with their regiment/friends and during weekend events 'joining a certain faction' is a bigger issue then during the week.
Another effect is that some regiments don't use the ingame 'voice' but only use 'Discord/Teamspeak ...', and for 'new/non regiment' players that makes it more difficult to fit in.
I firmly agree that it's a good thing to keep the factions balanced and if you really don't want to join a certain faction ... then just wait it out.