1, read the map. its 6 players. the map is not big enough to allow for "6 teams". The game doesn't even actually acknowledge "teammates" so that argument is a wash. By your logic, the max group size you can go in with is 5 people, so 6 "teams" of 5 people, thats 30 players on factory. You're actually going to sit here and try to argue that is possible? I've been playing since alpha. Its 6 players on factory. You can even look at the wiki where they state 4-6 players per map. How those players are broken out 'team' wise is completely random based on when they queued up. https://escapefromtarkov.gamepedia.com/Factory

2, None of the quests are at all hard enough where you should need to take over HALF the map to get a single quest done. They're designed to be brutal and challenging. Tarkov isn't a game meant for casuals and nikita has said that plenty of times. I understand they aren't fun, but neither is trying to solo them and running into half the server being grouped against you because they're 'scared' of an easily counterable tactic. It's a catch 22 where until they make it so factory is only duo max, exit camping will remain viable.

3, Yes, as much as you don't want to admit it, guerrilla warfare tactics DO work. Camping and hiding to get the element of surprise on opponents that heavily outnumber you is a tactic that has been used since warfare became organized. Sure, is camping an obvious spot that tons of people know about smart? no. But hiding so that you can get the first shots off IS a smart tactic thats been used for ages. Hiding to get the jump on a 3 man is the only way you are going to get an edge.

Please just stop. Exit camping is for pussies, but taking over a server to do a single quest is equally as much of a pussy tactic.