I honestly can't understand how or why anyone would accuse Trump of racism.
Ah, but you're thinking of English speakers. The left speaks not English, but a real-world analogue of Newspeak, which has the same goal as Newspeak -- to make thoughts opposed to the Party's agenda unexpressible -- but which works not by narrowing the meaning of words rationally, as the fictional Newspeak's working was explained to Winston Smith, but by overloading words with extra meanings, to harness the emotional reaction their original English meaning evoked.
Thus, "racist" in real-world Newspeak can mean the same as "racist" in English, or a person who opposes some program the left fancies benefits racial and ethnic minorities, or a person who has noticed illiberal aspects of Islamic Sharia and thinks we could do without them in Western societies, or a person who thinks that countries should be able to control who immigrates to them, or simply a light-skinned person of European ancestry under the dictum popular in the fever-swamps of academe throughout the Anglosphere, "all whites are racist."
Other handy real-world Newspeak phrases include "health care", which can mean what the English phrase means, or government-designed health insurance (so that modifying Obamacare is called, with as straight face "taking away people's health care"); "women's health care", which besides its English denotation also means abortion-on-demand (throughout all nine months of pregnancy, and with permission given to the abortionist to kill any children who survive the attempt kill them in utero); and lately, "court-packing" which, besides denoting increasing the number of seats on the SCOTUS now also means appointing and confirming Supreme Court justices the Left doesn't like.