But it isn't true
I know people at Kings and UCL who got AABBBBCCCCDE? You're making assumptions based on League and the name of the university haha.
I also cannot evidence a face-to-face conversation. You're being overly analytical, having a shot means A CHANCE. It doesn't mean a high chance, a moderate or mild one. It means a chance. It will depend on your competition that year, the course you are applying for, the other areas of your application, and each individual university.
As I said, lets agree to disagree. I cannot really be bothered to argue about this. Cambridge even say they dont have general requirements in terms of GCSEs and AS levels show more to them than GCSEs. A lot of people with 10A*s dont even get in. Theres more to it than GCSEs and you're misleading saying GCSEs carry a lot of weight because they actually don't. They carry some weight but in the grand scheme of things they dont, as long as you have good AS Levels and everything else goes well.