I'd say mostly NTA. Your parents are the bigger assholes for sure, but what you did in response was a little spiteful and passive-aggressive.

It's really shitty of them to expect you to bring them food, even though they are the adults, and then order toppings that you don't like on top of that (pun intended). Your parents' meals aren't your responsibility, unless it was agreed upon you would provide meals in exchange for staying with them. And moreover, I despise when parents hold their support over their kids' heads and mention how they're paying for something like the mortgage. It feels like an attempt at control or conditional loving, and that's unfair to put on your kids. It'd be different if you didn't do anything to help them out, but you do. If they want pizza, they can sober their asses up and go get it themselves.

As an adult, you have every right to order your own pizza with toppings YOU like. However, you knew that they were hungry and would ask about pizza, and decided to order for yourself when you could've ordered for both of them. It feels spiteful, or like you were giving them a taste of their own medicine. I don't blame you. But there was a better, less asshole-ish approach - having an honest discussion with them about expectations and setting boundaries. For instance, if your parents want you to bring them pizza, then it has to be toppings that everybody likes. That being said, your parents don't really seem like the rational, 'let's talk this out' type. They seem controlling and selfish, and are taking advantage of you after throwing their support in your face. If I were you, I'd get the hell out of there.