HCE 4v4 - Longest

I just got spawn farmed in a game of CTF on Longest. The enemy team, a lobby of three friends plus one unknown, stood around four corners lobbing grenades into our spawn locations. Two of us quit, I did not leave because I did not want to be penalised for being unable to do anything in a match. They captured the flag once ten seconds before the match ended, not leaving our spawn until that point. I would like to ask why this map is allowed in 4v4 objective matchmaking, or any outside of action sack or 2v2? It’s too small, cramped, and the fact that such a thing could be done was immensely frustrating, as was knowing I could either just continue to spawn and get shot by pistols while grenades explode all around a second later, or quit and be penalised for leaving such a situation to begin with.