It was written for any president abusing a state of emergency, not just Trump. And even in the case of a state of emergency, it would depend on what the government makes of it. Does it use the power to efficiently control a real catastrophe, like a massive flood or a massive EMP attack? Or does it use some minor, made up shit as an excuse to rule in a totalitarian way, like Germany after the Reichstagsbrand? France has been under a state of emergency for quite a few years now, I think, and they haven't gone mad yet. Well, not totally at least. So yeah, it depends. If you think that because emergency presidential powers exist and since Trump is an evil, evil man and thus will likely abuse them and should thus be immediately overtrhown, well, that's fine.
How come legal immigration into the US works at all? You think they're teargassing regular people at the border control points trying to apply for a visum? So if I wanted to apply for a visum to the US and work there and eventually apply for citizenship it's impossible, I'd get teargassed and beaten at the airport? Oh wait, you think me being white fixes everything. Look, if I'm in a foreign country and forget to renew my visum, I'm fucked. I'll either be very quick about getting it fixed, and hopeful that my office clerk has a good day, or I'll have to fuck off. I might not like it, but if I like it in a country I'll make sure I renew my visum on time.
Also, people who haven't renewed their visa are usually not on the outside of the fence, they're already inside. They're not the ones getting beaten up at the borders.
Last but not least, people getting teargassed at the border is not a new development under Trump. When a huge group of illegal immigrants try to rush a border, the border gets defended. You might not like the existence of borders, but that's the reality. Tear gas was also used under Obama, and Obama also held up entire families until their deportation. It's the sad reality of the existence of nations.