Why is this a prerequisite for having an opinion?
I've never driven a ferrari, yet i am of the opinion that it is fast.
I've never dropped acid, yet I'm of the opinion it messes up your perception.
I've never been in space, yet I'm of the opinion that it would be cool.
I've never been to Rome, yet I'm of the opinion that it would be historically interesting.
All that is true, but how can it be if I've never done any of those things?