I understand how someone can see a thumbs up as something rude in certain circumstances. What I’m having a hard time understanding is that some people seem to believe that the thumb up is ALWAYS rude.
What is rude, as you say, is the lack of a proper response, depending on the conversation. Not the thumb in itself.
First of all - I’m shocked that anyone would use a thumb up like in your last example. That’s obviously extremely rude and disrespectful.
Second of all - I’m shocked that some people can’t see the difference of the usage of the thumb up and believe that it’s always rude, regardless of context.