This is your biggest mistake, in my opinion. Celebrities of any stature are not dolls on strings that could be moved by public's expectations.
Just imagine what IF Taylor doesn't LIKE Celine Dion. I am sure this is not the case. But, Just IF. Does she have a RIGHT to not like her and not want to appreciate her? Does she?
There are some people in my life that are GREAT, but I don't appreciate them, since I have a personal view of them. Again, this is not the case here, BUT EVEN IF IT WAS - Taylor doesn't have to live by your expectations.
What you are saying sounds like it comes from an old dictatorship rulebook. If a certain person A /Taylor for example/ doesn't do what you expect of them, when person B /Miley, as you mentioned her, yourself/ does it, then person A is a bad person that needs to be condemned and publicly shamed.
It's scary how powerful people think they are, when commenting about celebrities' characteristic and morale. If that was your neighbor or your friend, you wouldn't be so quick to write this, since they could pretty much sue you... But when it's Taylor Swift, it's a free arena to judge and condemn. I myself have done it too, but only when the said person is CLEARLY doing wrong and being a bad example. Which Taylor isn't.
In the end, it's easier to accept that some people have a different reality than yours. And don't expect anything from anyone. You are not their mother.