Islam is a religion not a race. There's no way you can say anything negative about Islam and be a racist. Saying bad things about Islam is not even hate. Islam did it to themselves when their Quran commands them to kill the unbeliever, declares a permeant war against the unbeliever and especially singles out the Jews to be wiped off the planet. And after they Jews are gone then they will kill all of the Christians.
Not all Muslims believe this, and most don't even know about it because they never read the Quran. However, there are a huge number (about the size of the entire population of the United States) who's sole purpose in life is to murder every unbeliever on the planet.
Also the Quran says it is okay to lie as long as it promotes Islam.
So time will tell if Mamdani is actually on the side of the United States or on the side of Islam. Regardless he is definitely on the side of Karl Marx and that is as un-American as you can get.