This game is balanced, but the matches aren't - that's how it should be
In DBD there are perks and add-ons to counter nearly anything the other side can throw at you. From that aspect you can correctly claim this game is balanced. There is legitimately a way to counter nearly everything.
However, having potential counters to everything does not equate to balance in matches themselves.
Take a Ghostface set up for all the stealth he can offer that ends up in a match with a team of competent survivors set up to counter stealth. The fact that team had counters in place for his strengths doesn't equal a balanced match. They negated all his strengths. That gave them an advantage. It wasn't balanced.
On the other hand take the same survivor team from above going against an experienced leatherface. Those stealth countering perks don't help. The perks the leatherface is playing probably give him an advantage against a team setup to counter stealth. Things in that match are going to be skewed towards the killer. That isn't balanced.
I'm not claiming that makes it unfair. This isn't a call for any nerfs or buffs. It is an acknowledgement that matches are rarely balanced and I would say they aren't intended to be.
Don't get me wrong. When I first started playing I thought every single match was unfair if the balance went in the direction of the other side.
In other words individual matches aren't balanced and they shouldn't be. If individial matches ever became truly balanced we'd have never ending games because neither side would be able to gain an advantage. The game itself though is balanced because neither side has a loadout that can never be countered. If the game itself became unbalanced towards one side of the other there would be no point in playing because the outcome would be predetermined.