Trump tweets [1]:

I, as President, want people coming into our Country who are going to help us become strong and great again, people coming in through a system based on MERIT. No more Lotteries! #AMERICA FIRST

The problem with merit-based immigration - such as the RAISE Act - is the definition of "merit". In Trump's mind (such as it is) that boils down to money and skills. That's a recipe for selling U.S. citizenships to the highest bidder, resulting in even more like Eduardo Saverin. Just because someone is rich or has skills doesn't mean they'd be that good for the USA. A rich doctor might just be a carpetbagger and his kids might be worse. Someone who's poor or lacks skills might be an exemplary citizen and raise exemplary kids.

What would make America "strong and great (again)" would be more patriotic citizens who act like citizens. That's on a different axis than whether someone has money and skills.

Merit-based immigration denies the experiences of most Americans whose ancestors weren't rich or highly skilled. It's a libertarian plan that treats the USA like a shopping mall.

The impact of merit-based immigration on sending countries is also a very serious related issue; Trump would ultimately harm the USA by braindraining foreign countries, making the situations there worse and leading to increased terrorism and crime. See skilled immigration for the details on those aspects.

If Trump is as smart as he and his supporters think, then surely he can figure that out. In that case, he's just not patriotic enough to support merit based on overall worth to the USA, not just merit based on someone's net worth.

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[1] twitter · com/realDonaldTrump/status/952530515894169601