How are you going to fix this? If you were a weak developer there are things you can do to about that. Fixing a persons inability to get along with others is more difficult. So now they're in the position of firing you. You'd have to be really bad not to make it an unpleasant business and afterward it's going to take weeks to shake off the bad feelings.
As a hiring manager I'm never going be given a hard time for passing on what might have been a good candidate but I'm definitely going to hear it about hiring someone who makes their lives miserable on a daily basis.
See the problem now? That isn't a description of you but they don't know that but they've probably had experiences like that so they're simply playing the numbers at risk mitigation and when you give them reason to think that might be the way things are going to go they pass.
If I had a physical discomfort and asked online for ideas what it could be, and someone said e.g. "it could be that you're lacking magnesium, you should confirm that with a professional.", I would do so. I already asked for advice, to dismiss people giving them would be, well what's the point of me asking?
/s
It's a rule of thumb, not an absolute. This part I'm not being sarcastic abour: sorry if your social anxiety problems also include not being able to get nuance.
No good sentence ever started this way.
Did you consider their culture could not have the idiom? Or they could be young and inexperienced?
On a less emotional side, dude used the term "social anxiety", he doesn't seem like he's lacking the cultural know-how. Don't be so condescending towards people... or to put it in your terms, did you ever consider not to be so condescending in your opinions of other people?
Sorry to dang for breaking many rules.