It's ground beef. The rule is you must cook it to the proper internal temperature. This is reasonable food safety. This simply precludes medium as an option.

If they grind their own meat or use something like ground chuck or ground round you can get it medium.

Why is ground chuck safer than other ground beef?

Bacteria contaminates the exposed surface of foods. Pre-ground meat has a _lot_ of surface area exposed so the potential for contamination is high. If you get your meat as a chunk of chuck roast or larger primal cut, follow good food safety practices in how you maintain your workspace, and then grind the chuck and turn it into patties to be grilled the probability for serving a contaminated product is low.

The problem is that this is more expensive and time consuming so almost no one actually does this in a commercial setting. If you tell me you do this when I come over to your home cook-out I will possibly trust you to serve me a burger with some pink in it, but if your restaurant tries to sell a $6 burger that you let someone order medium-rare bad things are going to eventually happen...

There are small burger restaurant chains in Canada that grind their meat on the premises. Burger's Priest (they used to tout this, but since the franchising push, this link is the only mention about grinding their own meat - https://www.recipeunlimited.com/en/franchising/burger-priest...) and Holy Chuck Burgers - https://holychuckburgers.com/.

Some meat sellers mechanically tenderize (blading) their cuts of beef. This may cause E.coli on the surface of the beef to enter the interior of the beef. Costco was linked to E.coli cases in 2012 due to this practice. See https://www.consumerreports.org/cro/magazine/2013/06/has-you...

For added safety, you can even sear the outside of the cut, then trim the seared part before grinding the rest.

Same in UK. Family members keep asking me when we travel there "will my burger be done right". Uhhh..there's only one kind of doneness for a burger in these parts.

That doesn’t make sense. It’s beef.

If you can serve a steak medium, then you can also grind the steak, cook it medium and serve it.

A whole steak doesn't contain pathogens deep within, only on the surface, which is why ground beef is different situation entirely.

Then you get bacteria in the ground part, potentially, whereas a steak will be cooked on all the exposed surfaces.

Um, it’s beef. It can be eaten raw. Ever heard of carpaccio?!?

Only two reasons to ever cook beef: (1) taste (2) quality

The exterior of a cut can be seared and then trimmed off to get a safe chunk of raw beef.

seriously? No medium well, just straight up well done? So, hockey pucks? Ahh, now it makes sense. It's a law endowed by Canada's love of hockey

It's perfectly possible to cook a burger such that it's not dry but also not raw.