Why can't you block someone by their MAC address if the OSI layer 2, attaches the physical address to each packet?

I'm going through a textbook right now and I'm on OSI layers. For the second layer, Data Link, the book says

"Layer 2 Receives the packets and adds physical addressing by adding sender and receiver MAC addresses to each data packet. This information forms a unit called a frame."

But I also remember a while back I googled "can you block someone by their MAC address" and the answer was no you couldn't. So why can't a receiving user get the MAC address of the packet sent by the sender to block them?