The germans started with vagrants and the homeless as well in 1939
Few people know Adolph Hitler was one of the vagrants rounded up for camp internment, long before gypsies, jews and communists! According to William Shirer (the only biographer who probably knew more about Hitler than Hitler knew about himself), Hitler's first exposure to camp systems was at the Mannheim Men's Shelter where he was delivered by police! This was one of the reasons he fled when they started the draft for World War One to England where he slept on his brother Aleph's couch. It wasn't until he got a phone call from Germany telling him within 24 hours he would be convicted of criminal evasion of conscription he reluctantly got on a train and went back.
This record of his draft dodging arrived with him when he got to his unit in WW1 and they considered him an unfit draftee who could not be trusted with proper gear, so they gave him a pistol and made him a messenger, a career that usually had a lifespan of a couple of days in the first World War. His fellow soldiers generally regarded him as a massive flake tagging along with their unit who could not be relied upon for anything. When Hitler got done he almost made it sound like he would have won the the Great War by himself if the bolshevists had not betrayed him. His "capture" of soldiers during the war is rarely described correctly as a bunch of people looking for somebody to surrender to somewhere.
Hitler's "gas blindness" was universally diagnosed as hysterical spastics when the war was over and many people pointed out it was highly unlikely Hitler was anywhere near a mustard gas attack in his short lived military career. This is the actual sort of guy that Adolph Hitler was.
It is funny when you see this camp internment beginning in the United States in an identical fashion to Germany because it starts to make you wonder if all these historical cycles have little or nothing to do with cults of personality and everything to do with the populations of societies themselves. Right around the tenth generation of any nation, they start to go badly to seed and this camp nuttiness starts to seem like a good idea constantly. Got a problem with poverty and homelessness? Send'em to camps. People criticising the government? Send'em to camps. Pregnant unemployed single mothers with no insurance? Send'em to camps.
When the only intellectual tool you have is a hammer, every problem starts to look like a nail. Put some more of that toilet water on it instead of Brawndo, the thirst mutilator.