What can I do to make them understand?

Its hard to starve on the streets unless you're out on lil' house on the prairie. You're probably more into the companionship which is not negative by any means. I say just do what you feel is right so long as you realize all choices will affect you in 1 way or the other. As for them being "dangerous" mankind is dangerous period. No reason you should (or not) trust them anymore than ne1 else.