Well, to be fair, you've had plenty of warnings that he isn't a trustworthy or honest candidate. He's always done or said essentially whatever he needs to in order to win people over. That's what a populist does by definition. I very much doubt this is the start of a consistent foreign policy, I imagine it'll waver all over the place for the next four years depending on what the President thinks is popular.
I am not "team Trump" and never have been, precisely because I think he's a dishonest, unstable con-man. On the balance of information available to me, I thought his strike on Syria last week was probably the right thing to do (though I know less about the Afghanistan one so cannot really comment). This is hardly a wholesale reversal as it doesn't really have any bearing on the major problems I've always had with him.
The way I look at it is - a terrible president made one good decision and is still a terrible president. A broken clock may be right twice a day, but you wouldn't put it on your wall.