A meritocracy requires authority to function. The authority decides what and who is deserving of merit, by measuring how much it would benefit their own interests - primary among them, the furthering of their authority.

By pitting people against each other to prove their "merit" to the authority, the authority successfully maintains a hierarchy with them at the top, their merit-granted lackeys next on the ladder, and everyone who hasn't been deemed worthy of merit at the bottom of the pile fighting for scraps.

Those who have been granted merit then uphold and shield the authority that granted them the merit in order to safeguard their own position on the pyramid.

You can see a glaring example of meritocracy in academia with the tenure system that permanently distinguishes the chosen ones above their untenured subordinates. Every academic struggles for years to join the tenured ranks. They have to be cautious to never hold any kind of controversial, anti-establishment views that would be shunned by their peers, as this would result in them being denied tenure. Threatening the established order is the worst crime someone who desires merit can commit.

Those who have been fortunate and uncontroversial enough to be granted merit cling to their privilege to the detriment of everyone below them, the merit-less masses who have been deemed by the all-knowing authority to be undeserving of accolades.

The merit-granting authority can be a single dictator or a diverse democratic body of dozens or even thousands, it doesn't make a difference. It's still authority and it's still a class system. A meritocracy is a clear hierarchy that divides us into haves and have-nots. Deserving and undeserving. Worthy and unworthy. Good and bad. Rulers and obeyers.

With people fighting each other tooth and nail to gain the favor of the authority and secure their place under them or by their side, the authority's power is sealed and everyone ultimately loses. Whether they are one of the few who eventually get granted merit or not, they still wasted their life competing for the authority's favor.

"Anarchists" who claim anarchy is about meritocracy are diluting the meaning of anarchy to a perverse extent. What they're advocating for is really no different than garden-variety liberalism. They don't actually want people to be free or equal, they want themselves to be elevated above the riff raff. To be granted the authority of merit so that they can feel superior to those deemed unremarkable.

Equality doesn't come from separating people into ordinary and extraordinary classes.