In the initial sync python hook, as part of pausing the background thread we currently wait for mongos to retarget all shards.

In order to ensure that the mongos can target all the primaries nodes of all the replicasets in the cluster we call collStats for every existing collection/view. This logic is just a best effort and doesn't provide strong guarantee, in fact if a shard doesn't contain any data for any collection mongos will not try to target it at all.

In SERVER-72858 we already removed the same logic from the stepdown hook.