No they arent. Your imagination. Some Thais hate farangs cause the farangs have 50x more money. Nothing to do with masks.
A Thai woman in hotel tried to skim me for 50 baht on a car pickup. I called her bluff. She had no mask on. I kept my 50 baht.
Most of the anti farang stuff is $ related.
My main waitress in NK no mask the whole day serving customers! Nobody cared.
Some other women mask on 95% of the time. Some folks are chilled, some are not.
Try visiting 6 provinces next month. Get out more.