The Tykes produced an impressive performance to secure a point after Luke Chambers' opener for the Tractor Boys.
But it was no more than the second-from-bottom visitors deserved after an impressive display and McCarthy said of the leveller: "We didn't defend properly but they deserved a point.
"Not that I'm happy about it. In fact, I'm very unhappy about it but they deserved it.
"They were the better side and took the game to us. They didn't sit back and try and catch us on the counter. We would have nicked it if we'd taken the three points and I'd have been delighted.
"If you're the inferior side and you get in front, you've got to grind it out. That's how you progress. We'll take the point, put it in our pocket and keep it and make sure we keep picking up more."
Asked why his side have struggled to beat their fellow strugglers, he said: "I honestly don't know. It's one of those imponderables and I just don't know the answer.
"Maybe it's a bit more nervy, when you're playing one of the sides around you, but I'm not going to offer reasons. Sometimes it happens that way."