So Right: I could be wrong, but I distinctly recall being taught in my very religious school/yeshiva that if a person would not welcome tochocha, OR, if they have been told more than once, then it is assur to tell them, or tell them again.
So, why do it then? As I stated before, to make one’s self feel more self important. In which case, it is not a matter of Hakadosh Boruch Hu’s kavod, rather it become’s a matter of your OWN Kavod, and the public harassment and humiliation of someone else.