In the first case, the father commits an evil (car theft) to bring about a good (a car for his needy family). The correct moral decision is not to steal the car because the first principle of morality is to do good and avoid evil.
In the second case, the father has a choice between doing nothing and risking the lives of his family or stealing a car. Both acts are intrinsically evil, but car theft is the lesser evil. The father would be absolved of moral culpability for choosing the lesser evil.
In every case in the Potter books is Harry choosing the lesser evil, or doing evil so that good may come? Somehow I doubt that it's always the former.
Regardless, this is a tangential objection to the series. The central objection is that the protagonist is a practicing wizard/warlock.
Since you admit to being uninformed, your views on the subject are worthless.