Sheriff Beth -- who's in the public spotlight following the shooting of Jacob Blake and subsequent riots in Kenosha that led to 2 people being killed -- used the phrase "these people" multiple times as he described how he believed they should be "warehoused" ... so as not to allow the men to procreate.

The Sheriff went on to say it's time to stop being politically correct -- and though he specifically claimed race was not a factor -- he insisted "these people" should be put away for good.

Later in his speech, Beth said ... "In this country, in this community, in this state, we have to get to the point where we will no longer put up with the garbage people that fill our communities. They are a cancer to our society."

The case that got Beth so riled up was a retail theft in a mall that led to a car chase and a 2-car crash. At the time, Beth said he was so angered because the suspects hit another car being driven by a 16-year-old who just got his license ... though nobody was seriously injured.

The 5 suspects, aged 16 to 23, were all from Milwaukee and were all charged with felony retail theft and obstruction.

Beth addressed the media Wednesday following a deadly night in Kenosha, in which 2 protesters were shot and killed by an armed suspect. Cops later arrested 17-year-old Kyle Rittenhouse in connection with the incident.

The Sheriff suggested Rittenhouse was part of a group of people who asked to be deputized in order to help police patrol the area, something Beth said he wouldn't do because of the liability and chaos it can cause ... as evidenced by what happened Tuesday night.