that's fine for a huckster shilling for his steaks, water, ties, etc...
when the POTUS tells blatantly provable lies on a subject (the election) that he chooses to keep talking about that's a different story
In my opinion it's the price you pay when you elect a non-politician as President. He hasn't been coached his whole life to play the middle on every topic and avoid saying stupid things that will make him look bad.
On the substantive issues facing the United States, Trump is on the way to being a great President. He's doing exactly what he promised he would do during the campaign and he's doing it quickly. He has some minor flaws and saying shit like this is one of them. In the grande scheme of things it's very petty and the people that elected him don't give a fuck about it.
I notice you glossed right over the bit I said about the corrupt pathological liar Hillary Clinton. A lot of people dismiss her corruption and her bold-faced lies but then make a big deal about dumb shit that Trump says in passing. I find it amusing and it proves that a lot of people are dishonest themselves. They feign outrage when Republicans do things and then turn the other way when Democrats do the some vastly worse. Kind of like how people attack Trump as a "sexual predator" because of a crass comment he made once but ignore the army of women that have accused Bill Clinton of actual sexual assault.