Since if you decline they fire you. Yeah, this doesn't make sense since now they're still out someone for that shift AND out other shifts. But managers aren't logical or reasonable when they pull shit like this: they're vindictive.
In their eyes, it's more important to serve notice to the general workforce on what happens if you refuse versus the importance of any particular shift.
CONSERVATIVE REPUBLICANS. Don't sugarcoat it, CALL THEM OUT BY NAME. Otherwise they'll just pretend it's not them and do their damndest to act like they've done nothing wrong.
Even the ones who aren't actively protesting on behalf of the conservatives are still voting for conservatives, who end up making the claims that they can never produce sufficient evidence for.