[The purge] why does the government wants so hard to kill the homeless and poor?

I mean, are they really that bad to the economy? I understand they may be a scapegoat but it’s not a official reason the government gives to the public so it’s not that either. Like, i understand that maybe having welfare programs may affect the economy, but i think the purge will affect it way more. I don’t understand why the government would want so hard to kill homeless people and other poor people. I did not watched the movies so i am just curious about the premise, yes you can be curious about a movie premise or synopsis without needing to watch the whole movie. I want the answers from here and not from the movies because i know they are very violent and i don’t like this sort of movie
Edit: i searched for it and it said they believed it would reduce crime rates, do they really believe in that? I think even in the purge universe having the purge makes the country unsafe if anything. Also many poor people work low salary jobs that the rich depend on, i don’t think they are all useless