I have, and its disturbing. The homeless are already looked down upon, and while yes, some do have legitimate mental issues that can make them dangerous, it seems they are not the majority.
What bothers me is that people I've met saying this are in either the middle class or upper class of society. I mean ffs, anyone can become homeless if they lose all their possessions or assets.
This kind of talk should worry anybody. I'm usually not the one to classify things in this light, as I believe that it is a very serious accusation, but this reminds me of talk in Germany circa 1930s. It's actually this kind of talk that pushed me to the left, because I believe in human rights and right to life, over profits.