Trump, and the people who support him, aren’t really big on logic.
That being said, people who believe in multiculturalism really are delusional. America has the highest amount of prison population and social angst compared to other nations. It also has a horrible education system. It really is a “melting pot” and exactly the same as being hurled into an actual melting pot. Americans are stripped of identity and forced into overwhelming sameness. Americans have nothing to be proud of, it is one of the most emasculating nations where everything is illegal, and prostitution and sex has been banned by religious squares and angry dick-hating feminists.
The multiculturalism is easily explained when you think of America not as a country, but as a business. It is in the interest of any trade that all cultures recieve equality and treated as equals in business. No so much in social life. When a nation has 10 different languages and alien cultures that are expected to tolerate each other, things get pretty muddy and chaotic fast, not to mention having to wait twice as long when making phone calls in customer service while each language is repeated.
As for Muslims, that is where the liberal/SJW hypocrasy begins. The Marxist equality dogma says everyone is equal and to tolerate everything…yet we see what happens in Russia when Putin adopts the same Marxist attitude (Marxism started in Russia after all, it is a Russian thing.) Putin let part of Russia import and endless amount of Muslims, and look what happens in those parts of Russia. Sharia law where the Muslims kill any homosexual they please and what’s next, any of the unbelievers. So LGBTs and SJWs have a kind of problem. The Marxist dogma says to be a cuck. Yet, to be a cuck is to allow everything, and accept everything, even things that will punish you for being a cuck. And that’s where Christianity comes in. It pushes LGBTs towards the idea of self-sacrifice and turning the other cheek, rather being in favor of foreigners who hate them and who want to destroy them, after all Jesus says he who does not hate his own brother, is unworthy of God.