True but on the F1 Forum Helmut Marko says the team gave both drivers equal opportunity. And even if Vettel is 1st at RBR and Webber 2nd, both of them had massive opportunities to win the title this season, and both have chucked them away. We could easily have seen Webber pick up points in Valencia, not have chucked it away in Korea and to have won in Brazil and force the team to have to favour him for the title.
Just because a driver is the team's 2nd doesn't mean that results on the track stop him from being the team's leading chance.
I think you have to understand the psychology of it all.
If you work in an office, say. Imagine you and your colleague are the salesmen. Both of you have the same opportunity to make the same sales. You are both given the same phone/leads, etc. The difference here is that the bosses in your company are all chummy with your colleague. They are encouraging and maybe even giving some extra equipment.
It is plainly evident that your colleague is being favoured. This environment is not conducive to you doing better than your colleague. In this way, your colleague (effectively the No.1 salesman, is given all the ingredients to outperform you at your job).
I would also contend that had Vettel been leading the title race, in the run in (as Webber was), Webber would be asked to "support" his team-mate. This "support", as the season comes to a close, is quite normal. In fact it is quite abnormal for the leading title contender to not be favoured, as the season draws to a close. However, this is exactly what happened to RBR's No.2 driver, Webber.
With regards to RBR claiming that neither of their drivers are being given preferential treatment - this is utter nonsense. People following F1 for years will know that the No.1 driver always gets preferential treatment...this is normal. Furthermore, Webber, throughout the year has indicated that RBR have favoured Vettel, whenever possible.
In the last 20 years, I can only remember 1 occasion where the No.2 driver was given preference over the No.1 driver (as the season drew to a close) and that was when MSc was asked to support Irvine (1999, the year MSc broke his leg and couldn't compete for the title, while Irvine was in contention for the title). Those were extraordinary circumstances though.