I didn't come up with a technicality. It's written down. It's the law.
There is no federal tail light percentage law, just like there is no federal window tint percentage law. There are plenty of federal regulations that discuss obstructions of lighting devices.
Now you can attempt to justify your illegal painting all you want. You can equivocate your actions by pointing fingers. You can quibble over terminology and ignore the intent of the law. You can argue and piss and moan and try to blame everyone else. You can deflect, you can look for loopholes, you can pretend like its not a big deal. You can pretend like your lights aren't dangerous. But that doesn't change anything.
Your tail lights are illegal. /discussion
Again, good write-up on the badge mod.