This, I should think, is because the real prototype of all the strips wherein Eva checked expiration dates would tend to explain my argument very well indeed. While Lizzie isn't being lectured about problem hair or being told that she's too young to feel sensitive, the message of the strip is quite clear: "People who are more important than you are can't be bothered to care about the things you do. Kindly admit that nothing that you do can matter to them and feel ashamed for lying to yourself about your life being something anyone who matters could possibly care about and trying to waste their time on your meaningless life." This, as I've said before, is because the status-obsessed Pattersons' family politics are all about who's most important and who must therefore not be somehow diminished by wallowing in the concerns of the lesser. This means that when John was being a ginormous swinging dick by giving Liz the "problem hair" speech, he wasn't actually trying to put things in perspective. He was actually saying "Look at ME!! I'm King of Big [BOXCAR] Deal Mountain!! I can't be bothered worrying about your meaningless life and bullshit problems because if I did, I might realize that I'm not actually the victim of all victims surpassing all others! As punishment, I'm going to make you feel like a selfish little shit who can't care about others!!" Similarly, when Eva was checking April's expiration date, she was tragically pleading with her to not feel guilty about having her own God-damned wing of an enormous house because that would be a horrible thing to do to her.
The real payoff to all of this is, of course, his complete bafflement as to why it is that people aren't grateful to have their attitudes helpfully adjusted to his (and, given his tendency to see himself as the measure of all things, their own) benefit. I should think that he's still waiting for Liz to tell him that yes, she was too young to be sensitive about her looks and that she was out of llne making trying to make him see that she felt alone and lost.