What’s not being reported is what Trump said:
Trump said "if Mexico wasn't willing to talk about paying for the wall, there was no point in a meeting."
Mexico wasn’t. So he cancelled.
I think what he said was more like, if Mexico is not willing to discuss helping to pay for a wall that will protect both countries from smuggling and human trafficking, especially from Central America, then there is really no reason to meet at this time. It was very measured, his statement, as I remember.
I find it baffling. I think he will make concessions to them when they come to the table (they will), but as long as they do not play they get no say in what we do. I like it.