How many think this was mean? Yes or NO?!

How many think this was mean? Yes or NO?

A person (19 yr old kid) decided to let me know I had used a few run on sentences. He didn't know what it was but he didn't like it. He was very rude when he answered my question. I found one of his questions and let him know his grammar mistakes and gave him a link for proper grammar usage. Do you think that was mean?

3 days ago
My thinking was to show him how rude it was and that everyone makes mistakes.

Yes it was mean what he did, because he could have forgot about the run on sentences and just answer the question. It was alright for you to do what you did, because you were just showing him what he did back! <3