This looks vaguely like boletes but I'm absolutly unqualified to recognise mushrooms.
Yep, I think you are supposed to leave some to the people foraging after you.
Besides, it's not like you can eat mushrooms all day, because they have poor nutritional value. So it's rather a luxury than essential food for survival.
But hey, at least it seems they were cutting the stem rather than pulling the mushroom from the ground, so the mycelium should be safe.