It's more based around the idea that if somebody's ok with smashing in somebody's door to commit theft, that they're probably ok with smashing in the homeowner's skull, too, if they attempt to stop the home invader. Additionally, not all home invaders are mere petty thieves, there's plenty of instances of home invaders breaking into a home to simply murder, kidnap or sexually assault/rape the inhabitants. There's no real way to tell if the person kicking your door down is there for your TV or if they're there for your head, so it's better to just give the home's residents the right to utilize lethal force on anybody who displays the use of violence to infringe on their right-to-privacy by breaking in to their home without permission.

TL;DR: By living in a society, you must respect people's boundaries, otherwise you are violating their peace of mind, giving them the right to defend themselves if you display threatening behavior towards them, e. g. smashing doors or windows. No matter how bad your life is, you have no right to make someone else's worse unless they have directly and objectively wronged you, say, by breaking into your home and stealing your hard-earned belongings.

A good TV costs around $100. The average minimum wage is $9 ish. Therefore it would take 11ish hours of your life to pay for that TV. Someone stealing said TV is essentially stealing 11 hours of your life. Because they are stealing hours of your life they are in fact committing violence upon your person. In the eyes of the law that justifies lethal force. Ergo Try me bitch.