If I did that who would be there to hear them when they come back?

Good point. Not like it's any burden to follow zombies.

It is though, because you are carrying around the dead weight of that data in your follow list. Over time it adds up and can even cause some clients and relay to stop processing your follows correctly. Forcing relays to process all that extra data every time your client sends a subscription request causes strain and slows things down, degrading the user experience.

They ain’t coming back, lol.