Not voting for him, but I think I understand the mentality. He first spoke to the working class and more precisely those who had lower incomes. He promised better veterans benefits, higher pay, more jobs, blah blah blah.
He hit many sensitive buttons that people are passionate about and people ate it up.
But all he ultimately did was made it easier for big companies to get bigger and line his own pockets
https://www.citizen.org/article/lost-safeguards/
https://www.propublica.org/article/the-government-donald-trump-left-behind