Let me try to make you understand this from my point of view.
There is a person x, he's very strong. There's a kid that punches everyone he see's. This strong person isn't bothered because he doesn't feel any pain from the kid's punches, and can ignore him really easily.
Now person Y is physically weak. The kid comes and punches him, person Y is in pain and unhappy. Person Y try's to bring up the issue, but person X says "a kids punches cant hurt you, deal with it".
You are doing something similar. People have different mental stability.
You might be mentally strong, but there are people who are not. Flame actually hurts them.
Now you can be like person X, and be a close minded person who only examines one point of view, or you can open your mind and accept the fact that, words can hurt certain people.