You remembered correct (well, mostly correct)! Policies can set expectations for impacting domains, but can't set expectations for ongoing action.
Adding to what Olivier said, one of the reasons why we say "policies can't require action," is because it's just a common misunderstanding of what policies do (if you want an ongoing action, then you want an accountability instead).
If a policy does requires action, then it's invalid ("Yes, objection. NVGO, because that does not meet the definition of a policy.")
I shared this in the other thread that Angela linked...
An invalid policy would be something like, "Everyone must review timesheets." Literally, that is requiring action.
"Policies can't require action" is a nuanced rule-of-thumb. Yes, a policy can't require action in vacuum. But many policies require some action either before or after the domain is impacted (e.g. "Anyone using the company car must fill it with fuel after use" or "No one may use the company car without first signing it out on the property ledger").