True, it appears they will indeed hit Hamas targets no matter where they are:

“Wherever a Hamas target arises, the IDF will strike at it in order to thwart the terrorist capabilities of the group, while taking feasible precautions to mitigate the harm to uninvolved civilians,” the military said on Wednesday, reiterating previous statements.
The military has said the homes where militants live are “legitimate targets” even if civilians live alongside them.

However, it seems like going south is probably still in civilians’ interests, IDF says there are more targets in the north and once ground forces go in they are going to consider anyone remaining north of the Gaza river to be a potential enemy combatant:

The military said the order was aimed at moving civilians away from “Hamas terror targets”, which it believes are concentrated in the north. …
Military spokesman Jonathan Conricus subsequently said: “We are preparing the area for significant military activity in Gaza City. That is the next stage. That’s why we are asking civilians to go south of the Gaza River.” …
Israel renewed its warnings on Oct. 22, saying that anyone staying in the north could be identified as sympathisers of a “terrorist organisation” if they did not leave.
https://www.reuters.com/world/middle-east/why-is-israel-attacking-south-gaza-after-telling-people-go-there-2023-10-25/