Many diseases are caused by parasites.
2: disapproving: a person or thing that takes something from someone or something else and does not do anything to earn it or deserve it
The second one is probably the applicable one here. It's like they are bringing down the whole economy and think that they deserve it. I agree with your view that it's the people and I wouldn't want to be with them as well. I don't think I can understand why they choose to live like that and only think of themselves. You could also characterize it as selfish and will only do something if it benefits; hence "parasite" is the proper term.
There are many other possible descriptions for different types of people, but I guess that can be a topic for the OP for another time.