Fixing their home country is exactly what some exiles / refugees want to do - but they have no means, often no idea, of how to do it.
Some simply want to leave that country behind and make a new life elsewhere.
There has always been tension between immigrants and indiginous populations.
It is a problem that goes back to the start of city states and has been quite well documented for over 3000 years..... I doubt that trump, or anyone, will solve it in any of our lifetimes.

Trump's father was son of German immigrants and Trump's mother was from Scotland, so he should leave the country immediately! But then again, according to his logic that would apply to most of us but the Native Americans...

It is unbelievable someone this evil and this ignorant could rise to the most important job on this planet. That in itself is an indictment of what a desperately lacking species we are.

It would constitute hate speech here in UK