Barack Obama is a Muslim.Unless you are a mindreader, these statements have the same meaning.
If Barack Obama were a Muslim, he would not behave any differently.
The meaning depends on the definitions, of course. If Muslim excludes those who profess to be Christian, then he is not a Muslim. If Muslim includes those who were born Muslim and have not publicly repudiated it, then he is Muslim. Those are legitimate definitions. But if Muslim is defined by inner beliefs, then others cannot be sure, unless they are mindreaders.
Among those who claim to be able to perceive Obama's inner beliefs, some say he is an atheist, some say Christian, and some say Muslim. In my view, those disputes cannot be resolved.
He does appear to have unusual sympathies for Muslims, and those views do seem to have influenced many policy decision. Saying Obama is a Muslim is useful shorthand for a long description of those policy preferences.
Donald Trump is a fascist.These mean essentially the same thing.
Donald Trump's top priority is making America great.
The leftists who call Trump a fascist do not make any comparison to Mussolini or Nazi policies. It is nearly always just a meaningless leftist epithet, or based on some sort of mindreading about what Trump thinks or might do. Pro-immigration rivals and neo-con Republicans have also called him a fascist.
The New Yorker mag reports:
Part of the problem is a definitional one. Even historians who have spent their lives studying Fascism can’t agree on what the word means. Were Adolf Hitler and Benito Mussolini Fascists? To be sure. ...So why do they call Trump a fascist? They do not like him sticking up for American interests.
But if historians of Fascism can’t write down on paper what it is, they can recognize it when they see it. And when Vox’s Dylan Matthews interviewed a number of them before Christmas, they agreed that Trumpism doesn’t meet the standard.