He's not attacking. He's talking. How much of Dipper is even left in there?

"Who thinks you're a freak?! Name even one person!"

It would be easier if Pidge had any kind of idea where Dipper was coming from. It was true, he had his moments of insecurity, she'd certainly made note of those but....

"Why would you think you weren't smart? You're resourceful, you're clever, you always think on your feet!" She's shouting now, and she hopes with everything in her that he doesn't just think this is empty flattery or, if he does, he's really susceptible to it.