Then how do they know that they're not dealing in stolen goods? If they can't establish a chain of custody to a legitimate owner, then they're being irresponsible.
Did the owners just push the laptop under the door and run away? At the point where they receive the laptop they can say: "If the laptop is locked it will cost you $X to dispose it here. If it is unlocked we pay you $Y."
Set X and Y appropriately and people who can will unlock them.
In fact, there was a period of time when depending on latest os version and hw version, the steps changed.
The one time I bought a mac personally, the reseller tried to follow the correct procedure... But they used an outdated one. Contacting previous owner led to threats of litigation for phone call mobbing.
Things may have been more complicated before that, but Apple has made it as easy as it possibly can be now without telling thieves to just start grabbing every Mac they see.
"Erase All Content and Settings" did not exist in macOS Catalina. Back then, you had to manually boot into recovery and reinstall the OS that way, which unfortunately did nothing for Activation Lock, and was a confusingly advanced procedure to expect end users to perform. Now, someone just has to go into settings and click that button and macOS will handle everything.
Yes. And what is argued is that they should talk about stolen property. Because if they got the laptops legitimately they should ask the original owners to unlock them. If they can't or won't then something is suspicious. The laptops being stolen is the leading suspicion.