What's the point of sentencing someone to 7000 years in prison?

To be on the safe side?
Also, to break someone completely, mentally.
Forty years in prison; there’s a small chance you’ll see the outside, one day.
Life in prison (without parole); there’s not a chance.
Seven thousand years; same as life in prison, only worse (even after you’ve died, and you could look down (or up), at your self, you’d see you’d still be locked).

Just to show the public they were tough on him and meant business .

So if he gets time off for good behavior that it is negligible to his sentence.

I don’t know. It’s like giving someone 5 life terms, to be served consecutively.

To make sure they never get out of prison

It’s proof that the matter is taken seriously.

Also consider as a means to get media attention and thus ANY other victims would recognize him .

To let him know he is f_ _ _ed by someone bigger than him, letting him know how it feels.