You are naive if you think kicking a kid out for being a negative influence will leave a positive impression on the other children.
Exactly.
When a parent throws a child out of the house it is rarely, if ever, beneficial to the child or the rest of the children and usually only beneficial for the parents because then no one is reminded what ‘failures of parents’ they are. (I say that tongue in cheek because I don’t think it’s the parent’s fault that the kid went off but I think that when a parent kicks out their child, it’s partly because the parents think others view them that way.) When parents throw a child out of the house, the parents are throwing away their personal responsibility to take care of their children. If they throw the kid out of the house they are not trying to fix whatever caused the first kid to rebel and then, whatever happened that made the first kid ‘go off’ will make the rest of them go off too.