Yup, that is what Trump really is - a populist. More precisely an anti-intellectual, populist protectionist with some conservative positions that happen to be some big ones people care about now (namely dealing with the border and immigration). The protectionist part would be rejected by most conservatives but he is framing it more as nationalism which appeals to many people. And after years of endless "blame America first" and "apology tours" I do agree we could use a bit of nationalism.
I don't believe Trump is an ideological conservative at all. I don't think he is grounded in conservative thought and that means I really don't trust that he would default to conservative positions in office. However, before making the assumption that he'd go off the rails as President we have to look at who he is surrounding himself with. Going to someone like Jeff Sessions for immigration ideas is a good start. If he continues going to conservatives for help with detailed policy positions, a lot of ideological conservatives may have less doubts about him overall.
The fact that Trump is challenging the mainstream media narrative and attacking political correctness are two things I really like about him and as he is generally coming from the right in those areas which is somewhat reassuring.
Still, populism has a history of ending badly - whether that be the left or right versions. The idea that he is promoting that we'd all be rich and everything would be terrific if it weren't for Mexico, China, Japan, etc, is truly nonsense. There is no way to go back to the post WW2 world where the US was the country in such better shape than everyone else we could afford absurdly expensive union contracts and a monopoly on much of the worlds manufacturing/industry.
Anyway, I agree with your original point - when Trump or any candidate says something we agree with it is intellectually honest to say so. More than that, there is no reason we all can't be agreeable and compliment one another's preferred candidate if they do something deserving of applause.
I personally think that right there, almost 7 years of Obama bashing the sh*t out of America and his lawless ways, people are hungry for someone to come along and "Make America Great Again." Gee, who was the last President to do something similar? (No, I'm not comparing Trump to Reagan but one cannot ignore the very narrow similarities between them, and the similarities in the country's mood back in 1978-1980 and today.)
"Make America Great Again" resonates for a whole lot of reasons which I posted elsewhere and I don't feel like repeating here.
The day I put my "Make America Great Again" cap on (which I just HAD to buy because I agree with that sentiment!) is the day I'd be endorsing Trump. Until then, I'm still a casual/interested observer in the whole process.