I don't seem to remember such with these examples, nor do I see the echo-chamber MSM crowd saying the same thing with these examples of lifting words.  In Barack's case, it was to use the entire premise of a speech or a major portion of it, not just a paragraph to describe a similar situation. Or is it "Just woooords!"

mash 

But most of those other examples are very different.   If a politician is trying to make a persuasive argument about a specific matter, he might use memorable words from other orators if it they fit.   That politican should properly attribute those words in his speech to the original author, and if he doesn't he should quickly own up to having copied those words if asked about it.  There's little harm done, unless said politician was trying to pass off the words as his own.

But Melania's speech is a different matter.   She wasn't trying to make a persuasive argument;  she was introducing herself to the nation.   And she didn't copy a moving passage from a skilled orator....she copied a completely forgettable speech given by the sitting First Lady when she introduced HERself to the nation.   

It was embarrasing for her to copy Michele's speech, but it has now become outrageous that the campaign won't just own up to it.