No one said "murder a child for something his great grandfather did." What is being said is a family that is raised to believe in communist rhetoric isn't going to suddenly and magically stop believing in it if one member goes away." All that happens is you've now pushed the rest into more rabid fanaticism.

So if you're willing to die because you let a 14 year old live on to turn around and kill you in a few years as punishment, then good for you I guess.