Went to a camping in the Laurentians in Québec (Ste-Agathe) and there were those things near some camp sites. The sites are only accessible by footpaths. No car access. And if you bring a bike, you have to walk it up a hill, so I doubt they are bike racks.
EDIT: I have sent an email to the park and they have been kind enough to reply. It's just a type of fireplace with a grate. They didn't give more info than just this. Thanks to everyone for pitching in!
OP said there is one at each camping spot and you can see the camp fire right there. That seems very close to be a spot for a salt lick.
10/10 I jump the gun on that one. I read the words food and got way to excited.