Sure, on the facts the chances of harm and serious illness for Sam specifically were low, but the way people are buying toilet paper suggests people don’t always react rationally in the face of an impending pandemic. Once you release his name, everyone who knows and cares about him would be rightly be concerned for him.
If I was waiting on a COVID-19 test result, unless I had been in direct contact with people I probably wouldn’t spread word to my extended friends and family before receiving the result because I wouldn’t want to worry them over nothing. Also, selfishly, I wouldn’t want to spend the next 48 hours trying to put other people at ease.
I’m not sure why Sam and the club decided to keep his name out of it (it could be for the reason above or something else entirely), but it was their decision to make. Going against those wishes on a medical issue crosses a line in my opinion.
I don’t think there is a public interest being served by releasing his name (most AFL fans couldn't pick him in a line-up of one); it’s just a youngish journo trying to get a scoop. It’s different from an ankle injury – very few people die from an ankle sprain.
Out of curiosity, what’s the threshold death rate for when you probably shouldn’t (publicly) laugh about something? COVID-19 currently has a mortality rate of about 3.4%. I’m not a PR consultant, but I would probably steer the club away from making jokes about it as well.