I have to agree with you, her voice was ridiculous. And you're right, male characters with little boy voices aren't really a thing.
I liked the show, but I had a few problems with it. Bernadette's voice was one of them. The other was the insane stereotypes, especially as regard women. Penny was supposed to be the "hot one", so of course, they had to make her, well, less than bright, at least initially, because god knows women can't be attractive and smart all at the same time, right?
I could go on and on, but I need my coffee.