I think there is a fairly good explanation of what 'kissing teeth' is upthread. There's a video and everything. Could people look at that rather than continue to debate whether it's tutting or not?
OP - I can understand why you did it, but it probably would have been better - obeying the letter of the 'law' if not the spirit, to have put them all back on the wrong hangers, inside out, and possibly all on the same hanger, as mentioned upthread. And then spoken to the manager. Shop assistants are supposed to be helpful, at the least.
I've lived in very multicultural places, lived abroad, and have never heard the term 'kissing teeth' - or even seen it done (or maybe just never registered it).
And I completely agree that not sitting down poring the internet for the latest urban insults that are growing in popularity miles from where you live - that doesn't make you racist. It makes you normal. I wonder how many people understand yiddish insults, or Polish, or Urdu, or spend their free time understanding the etymology of the word 'drongo'. Who really has time to learn that belching is polite to belgians, or showing the soles of your feet is offensive in Japanese and Thailand. It's too far away for you to care that much, right?
Most people are too busy to worry about stuff that has absolutely no impact on their lives, and that doesn't make them close minded, just too busy to worry about useless stuff.