Most of Cammy’s damage comes from frame traps or shimmy.
Birdie has no reason to press anything during pressure. He wants to take the throw and be reset to an advantageous position. While cammy is trying to get back in, one screw up can lead to him getting more damage than she does.
His v skill isn’t really the threat in this matchup, at least not always. It’s the damage conversion off of everything, and the very low practical damage cammy has because he can just take a throw. When you factor in health, there’s no way cammy can last as long at this. Birdie is one of the few characters that completely out footsies cammy, so when he takes a throw its a really bad situation for her, whereas usually, she can reset to neutral and have an advantage still.
The best thing cammy has in this matchup is instant ex dive. But there are good tools to deal with that. In the case of getting hit, just take the throw after the reset. On block either vreversal or take the throw. If cammy needs to use meter just to get something like a throw I don’t see how this matchup can be even.
I’m sure any decent cammy would agree, and basically everyone in the cammy forum says the same thing about the mu.