I found it interesting that Cuban would attack Trump since they are very much alike. Both are very rich and both are celebrities and appear on reality television. Also, both are known for being outspoken and brash. Cuban has better hair though.
I think Cuban wants to be heard and asked for his opinion. Trump, I think, just assumes that everyone wants to hear what he has to say. Trump, to me, is the last of old money thinking that some are just destined to be better than everyone else and we should all just accept that put them in charge. I think Cuban loves the sound of his own voice as much as Trump does, he's just somehow less of a cock about it.