I see this a lot. But the dichotomy — font-end vs. back-end — is false. When observing a woodworker, I would not expect her to have to choose between designing a Windsor Rocker and turning its back posts. Why we impose this separation of design-thinking and system-thinking on ourselves as coders is a mystery. Of course, I say that from the perspective of a full-stack engineer.
I build things for humans.
I don’t make much distinction about whether those humans are other coders or end-users. They all matter. Or, they should.
By the way, if you choose to specialize in more back-end or front-end concerns, that does not make you any more or less “hard-core” (talented? intelligent? valued?) than someone who specializes elsewhere.
Care confidently about the things that matter to you.