Was I too hard on him?

[NiallC]

No one's really in the wrong here I don't think. He had no reasoning to think you are gay because you're not stereotypically gay so he couldn't help it. But you had the right to say it how you did because there was always that small chance that he was talking to a gay guy and should be careful.

[charley]

If you feel really guilty, apologize. Nobody knows what other people think or why they do what they do. I don't know exactly why I do or say some of the things I do... in a conversation, these things just slip out sometimes. Maybe you remind him of someone who bullied him in his past. Maybe he tried gender-neutral language and got called on it sometime in his past... Me, I'd let it slide & just be nice.