Sometimes you just have to let the words go, don't hold on to them, they are only words from a person on the internet.

Maybe both of you were at bad point in time and just happened to have a clash of viewpoints. Sometimes you just have to agree that you disagree on things.

There are some options-
PM and try to resolve any feelings off forum
ignore the persons words and move forward

We all need to try to not take words on any forum so personal, most of the time we really have no clue about the real person behind the words.