Is AUTHOR wrong in the post ? POST : tl;dr at bottom

So I'm visiting my family because my mom had surgery the other week and one of my parents' friends was there, who I had never met before. He's a pretty nice guy, and pretty funny. Anyways he somehow ended up cooking for us (I think he offered), which I thought was nice, and he was saying how he's cooked a lot supposedly and he's learned a few cooking tips and tricks from his "travels" that he might be able to show me.

So when it's all done we're all eating in the living room and there's a bunch of common food like corn, mashed potatoes and whatnot, all tastes the same as any other that I'd had, but the thing is is he cooked big hamburgers for everyone. The one I got was thicker than most but not as wide. Just from the habit of other people not cooking my food thoroughly before I cut into mine to make sure it was done, and obviously it wasn't, like at all, in the middle. It wasn't really a big deal to me, I've undercooked things for my family before, other family member have, but we all know to check and we generally just laugh about it because it doesn't happen too often.

So since mine was undercooked I just ate everything else and then I went back into the kitchen and started cooking my hamburger. I could hear over the sizzling hamburger for 5 minutes, the friend asking what I was doing and my dad said that I like them burnt, which he knows I don't. They then talked for a couple minutes while I was cooking it about how weird it was I like them burnt. Then my brother came up and told me it was disrespectful to do that, but he like to give me a lot of shit though. Anyways this ended up in a small-scale argument between my dad brother and I about it.

So, AITA? If I undercooked something I wouldn't feel disrespected at all if someone did that, especially if it was as pink as mine was.

tl;dr my parents friend cooked for us and didn't cook my hamburger thoroughly so I cooked it more on the stove and it apparently insulted him.