A major difference between the plastics delivered to a supermarket versus a refuse transfer station is the material delivered to a supermarket is clean. Much of the supermarket material has been prepared and packaged without being in contact with humans until it is placed on the shelf.
Produce and meat is an exception, but still, it is being prepared in controlled environments by trained workers. By contrast, recycling comes from unregulated households where many residents are likely to give little thought to whether they have coughed or sneezed on a piece of material before throwing it away.
Plastics and aluminium cans are likely to have saliva residue on them, which can be spread during the manual sorting process at refuse transfer stations. This is an unnecessary risk to our recycling workers during the COVID-19 pandemic, as recycling can be safely cleaned at stored at your home or place of residence. If you do not have space to store recycling, put it in with your rubbish.