Manhood, not quite.
A gigantic fuck you and middle finger to all of his political opponents who said he wouldn't do it? Absolutely.
There are many people in the United States, and even majorities depending on the wording of the questions asked, that want to reduce the level illegal immigration or even legal immigration.
What's a practical way of handling illegal immigration? Increased spending on border security since no one ( that's serious anyway ) is saying the wall alone would solve the problem though it would help. That's why Trump doesn't just want the wall: He wants a significant increase in detention centers, particularly beds, a far larger border security force including ICE, better monitoring equipment, closing of loopholes, denial of welfare, shutting down sanctuary policies and yes a wall on the border.
It's a whole package of things. The Wall would help matters, just ask Hungary how their fencing worked for them: Pretty damned well actually.
Whether or not the US should adopt these policies is a different matter, but discussing the practical issue is nonsense: If you want a reduced level of immigration these are things that would achieve it.