Sorry
This bit of the thread is baffling me.
I assume that most of those posting are talking about the situation in Class A and B airspace.
In my limited experience, mainly outside of this type of airspace, taking TCAS over ATC is quite dangerous. In Class G, for example, there are many a/c either not squawking or using Mode A only. For them to ignore an ATC contact and only work off their TCAS seems to be perverse.