This is just a standard fact of life for expats in Japan. I lived there for a while. I realized any meeting of foreigners would eventually devolv into everyone trading stories about how they'd been discriminated against that week. I met so many Japanese who were friendly and open and wanted to get to know me. But when you needed to get something done, you'd find office-workers, managers, cashier's, post office workers, etc would rather just not deal with you. We called it the gaijin card when you would be especially rude and assertive to get your way. It often worked but it sucked having to be a dick just to get basic respect.