Yeah I completely understand why people are angry, I would never vote for him myself
But I'm not as surprised as many others are that he is so big
He has big plans for change on multiple big topics such as inaffordable healthcare, a lack of housing, high rent, the bad economy in general.
However he is anti-islamic, which is his most contested political point. He is very outspoken and openly anti-islamic, which is why most people refrain from voting for him (including me), he is too extreme. In The Netherlands he would be considered one of the most right wing parties, however in the USA he would be extremely left-wing so thats a bit hard to put into perspective
I think he got about 23% of the votes, which is quite a lot of the Netherlands, around 2.3 million people