There's definitely a point in the movie where they squander your sympathy. The kids tutoring their kids isn't so bad (though certainly the second one is more a con than honest tutoring), but as soon as they start to push the other employees out of their jobs, they're advancing at the cost of other poor people. Though some of those others are also dishonest, like the lady with her husband living secretly in the basement.

On the one hand, it's easy to dismiss them all as evil people, but on the other hand, people must be pretty desperate to live like that and do things like that. Extreme economic inequality puts a lot of strain on social relationships.