Well in the first example that would also be racist, so no, no double standard. Secondly, Trump's comment in context was about all Mexicans, then as an afterthought he added that some *may* be decent people.
Like Jeremiah Wright? That was covered to death by the mainstream media back in 2008. Obama, unlike some folks, has jever seemed to believe that his preacher is speaking the word of god on every issue.