Why is that even necessary?

Essentially you’re guilty until you declare yourself innocent, and you need to prove innocence if the Beeb’s minions turn up at your house? What if you didn’t realize you needed the license because the rules around live broadcasts and battery-powered devices are so absurd?

People get sent to jail over this ridiculous situation while the government cheers from the sidelines.

Yeah it's extremely messed up and BBC likes to pretend it's not really responsible for it by hiding it under the guise of a "TV Licencing" body to distance itself [1]. I used to be pro-national broadcasting but honestly the quality of shows they produce has dropped so dramatically and how biased their news coverage has become I refuse to ever pay for it again.

[1] : https://en.wikipedia.org/wiki/Television_licensing_in_the_Un...

Why not simply charge for the BBC?

If you want to unlock it pay X$ per month. See how many viewers are willing to pay for it. That's what Disney and Marvel did, grossing billions of dollar in the process.