This is a really naive take in my opinion. Edit: it's naive
at best. Sounds more like you don't want to accept that bad shit is happening in the world. This has absolutely fuck-all to do with cancel culture and everything to do with selfish people spreading a dangerous disease.
You can make the same argument about seatbelts. The majority of people wear seatbelts because they've been asked to and they understand the danger of not wearing a seatbelt, for both themselves and their fellow passengers. But some fraction of people simply don't care, and well-intentioned people even have a tendency to say "oh just this one time." And that's why we need enforcement.
Look at this like engineering. With a large enough system, you are always going to have some components that fail. When your network has a million machines, you don't get upset when a server goes down, you just engineer some tolerance into your network, define processes to handle them, and go on with your life.
Human life is not redundant. Moreover unless you're able to outright deny people medical care for their negligence (which we can't do), unnecessary Coronavirus cases put more burden on everyone. Just like seatbelts -- even if you don't personally care if you get severely injured in a car accident, the EMTs don't have the ability to just leave your selfish ass dying on the side of the road, even if you want them to. You just wasted a lot of other people's time, energy, and money as a result of your carelessness.
If you can take simple measures to prevent components from failing, you should, especially when component failure is an expensive and intrusive proposition, even if it doesn't mean the total failure of the system.
Not to mention the fact that humans are notoriously bad at making rational utility-maximizing decisions. People often only come to regret their actions only after they've been forced to face serious consequences for their actions. Yes, this is slightly paternalistic, but it's yet another argument in favor of enforcing quarantine-like laws with actual penalties.