LOL tbh this is not the first time I notice how they hold those glasses just like you :D I just sigh really loud and promise myself to teach them one day :DDDD
Nice to know I am not the only one. I like fine wine and depending on the glass used (which depends on the type of wine) such glass must be held differently.
Same with spirits. Cognac is not served like armagnac and cocktails must not be held like wine glasses.
I guess this is a very European pet peeve. :)