You are probably right. The below documentation is what led me to believe that it might not sync at the start.
"If automatic syncs are not being used ("enable proactive sync" is disabled) then syncs from the IdP must be initated manually by an organization administrator. "
Also, it's weird that I have an Azure group that contains 4 users which I have added to the Meraki-IdP-Sync application I created, but now when I go into users, there are 20 something users that have been synced. It's just really unclear how the sync part is supposed to be working.