No one has EVER said Trump is another Hitler.
Mussolini wasn't another Hitler either, neither was Franco or Salazar (Portugal). And no can say if America will become another Nazi Germany. But the parallels certainly exist, and imo they are far from tenuous.
It is wrong to try and predict Trump's future policies with Hitler's excesses. The first hasn't happened yet, and the latter were the result of wartime. Browning talks about this at length! He agrees with you! However, there are eerie similarities between Trump's rise to the Presidency and Hitler's rise to power, which are outlined in Browning and painstakingly documented in Shirer.
We don't need death camps for there to be Nazis.