> When I see that a discussion is not progressing constructively (as I observed from your first response to me)

You offered unsolicited advice. I didn't take it personally, I tried to reply with arguments.

> I'm not interested in tit-for-tat back and forth

Just because I don't agree with the arguments you make it doesn't mean I have anything personal with you or that it is tit-for-tat or don't like conversing with you. Quite the opposite, the more difficult and challenging your arguments are, the more I enjoy the conversation.

Edit: Removed the "I am having doubts if you were interested in an open discussion in the first place." Please disregard it.