I hate to break it to you but you're not the only ones who get double teamed. I have seen every side being horded by the other two.
Yup.
Back in my days before I played under the name of Tinkles. I switched sides, and witnessed the 2 v 1s on all sides. Which, I don't complain about, I actually enjoy it.. more targets! Plus, in a game that has tactics and in a round-about way encourages tactics. Attacking an enemy that is already being attacked by one force is smart, it's just taking advantage of the opportunity at hand.
So Knights are attacking Rooks and some Bishops see this, so Bishops start attacking a Rook or even a Knight base because both of those sides (K & R) are busy elsewhere.
In this scenario Knights and Rooks could say they are being 2 v 1'd, because they are pre-occupied elsewhere and a 3rd party is showing up that wasn't originally in the fight. That is a fair assessment of it, but to say your side is being 2 v 1'd all the time is quite.. foolish in my opinion.