They misunderstood your bug report, but they certainly didn't tell you to "go f* yourself". In fact, someone later relabeled the ticket as a compatibility issue with MySQL after you clarified the problem.

I'm a lead developer from TiDB, and thank you for voicing your experience regarding reporting bugs in our community. I can assure you that our team member would never ever offend you, or any other developer contributing to TiDB, in such a way. We are grateful for your participation and support.

Could you send us a link to the issue you are referring to, so we can look into it more and make sure it's resolved? If you have any other issue, feel free to email me directly as well: shenli@pingcap.com

Thank you for your feedback. TiDB's progress would not be possible without people like you.