Footballers could catch covid in the supermarket, taking the kids to school, during training, at work (some other teams in our league are part time). As for socialising, it is legal to go to the pub or restaurant if you don't live in a tier 3 area.
How do you judge how these players got the virus? How can you tell if they broke social distancing rules?
If you start punishing people for having COVID, not only is it completely ridiculous, it would have very bad unintended consequences. The illness will be covered up. Clubs will play on and the virus will be spread everywhere.