That's nonsense.
If you look at the pace of the two drivers at the end of the year, you would see that Vettel was not just a little bit better just a different league better. Without the DNF in Korea he would have won the 4 last races. Allowing Vettel to race for the WCC was the only reasonable choice.
So are you suggesting that Red Bull made decisions about team orders based on Webber‘s lack of pace in races that hadn‘t happened yet? When they allowed Vettel to finish ahead of Webber in Singapore and Japan, missing the chance to increase Webber‘s championship lead by 10 points to a rather healthy 24, they based that decision on the advice of a very accurate fortune-teller who said Webber was going to bin it in Korea and then drive very slowly in the last two races?
I‘m not questioning that, as it turned out, the decision they made was very good for them I‘m questioning the notion that they could possibly have thought, at the time, without hindsight, that they were increasing their chances of winning the title by allowing Webber‘s championship lead to be needlessly eroded by Alonso. And I‘m speculating as to why they made the choices they did. I know Vettel fans will always take the view that they did it because they were somehow mesmerised by Vettel‘s star quality, or because they‘re all-knowing geniuses or, most fancifully of all, because Red Bull don‘t believe in team orders. But I don‘t buy that and I think Mateschitz and Marko blocked team orders in Webber‘s favour because they were only bothered about the Red Bull junior, not about winning the WDC for the team, and certainly not about some stop-gap driver left over from when the bought the team off Ford.