It might be blocked in the seat map, but not removed from sale meaning it can still unblocked if enough seats are sold? Whereas if it is removed from sale it would lower the available seats to be sold and thus lower revenue.

Similarly to how some seats are blocked by default on AFKL, like 1C on the KL737, or the bassinett seats: those seats are not available to be selected ahead of time, but they are sold and selection opens up once certain conditions have been met.