Why doesn't Ms. Houston acknowledge Charice effort in singing her tune?

Idk maybe it is just me or what. I notice Charice is always singing Whitney Houston smash hit songs( I have nothing) every now and then yet we never seen or heard that Ms. Houston have tried to reach or shake her hands on stage or in any gathering of celebrities in New York city or else where. Charice was acknowledge and introduce to the world by Ms. Ellen DeGeneres and the famous Oprah and David and others but not Whitney? Why what is wrong? Is she intimidated by this little Filipino girl from the Philippines? We know Whitney have an attitude problem before she became somebody in Hollywood. Just like her famous movie with Kevin Costner "bodyguard". She portray the role just like the way she is. Because I find every American is flabbergasted or amaze with Charice but not Ms. Houston. Charice has met Celine Dion and other superstars of music in Hollywood except one, the person who sung the smash hit "I have nothing". The only question is why. Because of the fact, Charice is a Filipino from a poor country like the Philippines? So what is your opinion on this? Thanks in advance.