I know people who were fired for refusing the Covid shots. I even know one who was fired for refusing a "voluntary" daily testing program.
No, these were not caused by a federally mandated vaccination requirement for the general public, but they happened anyway. The Biden admin wrote an OSHA mandate which pressured businesses into mandating the shots for their employees, even though the mandate clearly wouldn't (and didn't) survive legal scrutiny. President Biden posted to the official @POTUS account, among other things: "The rule is now simple: get vaccinated or wear a mask until you do."
I pointed out to people at the time that none of these threats were actual laws, but there was a clear effort to convince people that they would have no choice but to get the shots eventually, and threaten and browbeat them until they did, and it wore people down. A lot of employers jumped the gun and complied, forcing it on their employees, because they didn't want to wait until the last minute to deal with the mess it would cause.
To tell people now, "Hey, it was all voluntary, bro" is to be unnecessarily crappy to people who were just trying to keep their jobs so they could feed their families.