Part of the problem with the POTUS misspeaking or making gaffes, including those that you just mentioned (Bush and Obama), is that there is a higher expectation from people of the person in the job. It's like when people went crazy because Mariah Carey couldn't lip sync her own song on her New Years Eve performance, I believe it was. If little Billy messed up in the school play, he wouldn't be the subject of ongoing ridicule and attacks. But Mariah was, because she's a professional and people expect her to know her job. Part of the job of POTUS, a very big part, is communication.
I will attribute this Sweden thing to Trump misspeaking, and not doing a good or even normal job of stringing his thoughts and sentences together. He has to work on that if he has any hope of being well received by Americans and the world while he's POTUS. But he has told some pretty whopping lies, like the one about the illegal voters being bussed here into NH. That not only is a lie, but it actually denigrates the state and our voting operation, which as you know is very important to us because of our first voting status, both in the primaries and the general election. There was no reason for that lie other than he couldn't bear to learn that Hillary won this state, even by a small margin. That was simply put very un-Presidential of him, and intended to malign New Hampshire.