Easy meta breaker. Mage and Warlocks' greatest weakness to their questlines, is conceding. It's the only way.
Honestly though, I just concede against them. No fun in playing against a deck that isn't willing to play against me. Been waaay happier, and they are more spread in the meta, so at least 3 out of 4 games, are not them. I can still climb, and not be bothered to play against a noninteractive deck.
That's pretty much the correct approach if you are using a deck with less than a 40% win rate against them. It's exactly what aggro decks used to do against control back in the olden days.
Gotta love assumptions... I don't even care to win against them. I just don't want to play against them. I never said anything about beating them? Also, using decks with a >54% winrate, and the occasional toxic rogue if I'm feeling kind of funny.
I don't think he was insulting your deck in particular. He was saying that if the deck you are using doesn't fair well against Mage and Warlock(40%) then conceding is the correct option anyway.
If my deck smashes Warlock and Mage, of course I LOVE queueing into them.