I think there are several other more worthy 'Worf to DS9' continuity nit-picks than this one. Things like this:
TNG (New Ground): Helena brings Alexander back to Worf on the Enterprise because she and Sergey are too old to handle him.
TNG (Firstborn): Worf adamantly opposes K'mtar trying to send Alexander to boarding school, arguing that his son belongs with him.
DS9: Worf sends his son to live with his now even older parents who didn't want the kid just a few years ago.
This is the stupidest nitpick I've ever heard. Really? I wore a black shirt today. My girlfriend said I looked good in black. Guess what? I wore a black shirt a couple of days ago too.
So characters are not allowed to change their attitudes? Maybe Worf thought it was the honourable thing to do and raise his son on the ship?