Indie-dev life.
Just wanted to provide an update to this. I actually responded back to him in a very civil way, and he/she responded back much more politely. I've noticed this trend in general:
Upset person comes in guns blazing.
I respond by giving this person a big hug.
Person initially confused, but then defuses and gives a light hug back.
Doesn't always work, but most of the time it does! It can be hard, but always be kind to people! Especially to those who aren't kind to you. They need it most.