If I face a premade that's about to stomp me I'd rather have them try to win the game as fast as possible so no one is losing time or getting the afk debuff.
So, in short: Always play to win
I think that "playing not to oppress" is compatible with "playing to win":
7 twinks 3 levelers on one side, 1 twink (you) 3 f2p with bg blues 6 levelers on other side.
3 options:
A- the 7 twinks use pandaria ilvl 28 vendor gear with no chants, no engi and no alch. Bg weapon or white weapon based on the leveler classes;
B- the 7 twinks use standard gear, but UP specs. Dunno how much you guys tried, but fire mage still does loads of dps, same as survival hunter with only ranged (melee swap for harpoon is ok for gap close on efcs), same demo lock;
C- they play with standard spec and roll over you, make the f2ps and levelers feel oppressed, make them not queue again, make queues longer (you now have a bracket with no f2ps and no levelers, given all the complaint I'm quite sure it's dead).
What I think is missing from you argument are the fixed times of bgs, since you don't wint at the 100 kill, but when objects are done.
3/6 min queue
2 min to start
4-7 min for objectives to finish (I didn't time anything, going from memory, 3 and 5 bases ones may be faster, azerite one and cart one may be even slower).
the B option, the one I normally go for when I solo and my team is clearly much better than the opponent, won't take that much longer to win in comparison to C, given this fixed times, but it will not make levelers feel oppressed (or quoting a few of them, violated), and could get you (twink in the worst team) some space to make some plays and feel like you can still do something.
Option A, with the 7 twinks that modulated their gear to match the opponent team as the game goes and they understand what they are up against is clearly a dream, but it's the one I would prefer most clearly.
I would like to know, which one of these 3 options would you prefer? Would it still be C? Would you really prefer to stay at the boat, base or gy and having wasted from 9 to 15 minutes than having a challenging bg (option A)? Do you really think that the few minutes more B would take to win (2, 3 max I think) are not really worth for the overall health of the bracket? It's ok to waste 6- 9 minutes (comparing to afking out at the start and queueing on a different char) but 2-3 min are not ok?
I think it's wrong to think about this only from our point of view and not consider the overall bracket.
Actions have consequences, overfishing as a concempt is very much real and applicable in many different areas.