Texas isn't the only place where one is allowed to use various levels of force to defend various persons or property. That's not the point.
Castle Law may protect you if it comes to court. Having the right to use lethal force doesn't mean you'll survive the attempt. It doesn't physically protect you from the offender, or the offender's gang, friends, cohorts in crime, or what have you. Maybe if you think you're Batman or something you may feel that you can interfere with impunity, but most folks are still scared of knives, bullets, and repercussions.
I don't advocate putting on tights and a cape, but if somebody tries to take your lunch money, make a stand and say no. Because that's what our founding fathers understood and even died for.