Look, it's still a reasonably free country, and Mitt Romney can say whatever he wants. I don't disagree with all of the points he made against Trump in his speech the other day.
But in spite of the fact that Mitt has demonstrated considerable smarts as a businessman, and he's a decent guy, he's always come across, in the political arena, as a kind of doofus. And I certainly think this is a fair question: "Why Didn’t Mitt Romney BRUTALLY Blast Obama Like He Did Trump?" For that matter, why didn't he actually endorse one of the other Republican presidential candidates before now? This is a basic fact about RINOs: their most fervent, genuine contempt is reserved for people in their party who don't accept the GOP establishment's estimate of its own worth.