Wouldn't you agree that COVID19 has had a much more profound impact on society than the seasonal flu? They're apples and oranges.
Over 98% of patients hospitalized in May with COVID19 weren't fully vaccinated, the beds they occupy are a valuable resource and are preventing important surgeries from taking place. Someone who doesn't want to get vaccinated because they feel they're at low risk from severe illness? Alright fine, that is defendable but so is the argument that they're being selfish. They aren't doing their part to develop a heard immunity that is going to protect vulnerable people who can't derive the same benefits from the vaccines.
It's like putting away a grocery cart after you've unloaded it into your trunk, there maybe no rule forcing you to put it away, no one is forcing you to do your part, but its the right thing to do. If the wind blows it into someone else's car after you've driven away its your fault even if you never see it happen or have to pay for the repairs.