I dunno what's most emotionally resonant, so let's play a few tunes and see which one works.
1.
Legally, you do have something to hide. Estimates are 3-7 felonies a day, due to a bloated law code. In most cases they're not enforced, but if the government suddenly decides it doesn't like you, there's barrels of rope to hang you with.
2.
Bunch of rioters saying it's okay to punch nazis. Only, they get to decide who is a nazi or not.
How this plays out practically is, if they have your life on file, they find something to demonize that grabs you and not them, demonize it, and now you're a nazi.
3.
You do have something to hide. Nobody is perfect, but humans are such that we all have to pretend. If the government decides it doesn't like you, it drags your dirt into the light, but not their own, making it seem like you're particularly dirty.
4.
So look, basically with sufficiently low privacy, the government can just nail anyone it feels like nailing. Zero privacy is equivalent to jailing political prisoners and letting the king have the power of life and death. Historically, governments uniformly abuse their power.