Why do people get rude at me if I can’t figure out a homework problem?

I was asking about a math homework problem and some said, “You can’t figure that out? For order the operations you solve the numbers on parentheses first, then divide, multiply, add and subtract). Come on! Do the math! This isn’t rocket science you know. I’m not helping you with that. You’re a high school student, age 17 and you can’t figure this out? That’s pathetic.”
Wow that was very rude and harsh of that person to say it on my face. I almost cried but didn’t.