[PapsEdisa]

Williams are merely defending their interests, as I would expect them to do. Because of their non-involvement with manufacturer stakeholders, and the fact that F1 is their only business, those interests are not identical to those of some other teams.
When we see Williams defending their possible use of KERS, we should remember that at least 2 of Williams' drivetrain projects in the past have been rendered moot by FIA regulation changes in a non-consultative way. The Williams 6-wheel car project of 1981-1982 was rendered irrelevant when the FIA changed the regulations to say that cars could only have 4 wheels. In 1992 their CVT project was rendered irrelevant when the FIA banned any form of CVT transmission. IMHO that latter ban was deeply at odds with the interests of road car manufacturers, for whom a true lightweight CVT system would have been a highly useful and very "green" part of a drivetrain solution.
Now FOTA is trying to do what the FIA did to Williams in the past - ban a technology where they have done a lot of R&D for their own version of the technology. Since Williams is back as a FOTA member, they are using their membership and their KERS project as a bargaining tool, but I believe that they are genuinely interested in racing it. Like many teams this year, they do not have the track testing time to refine it to the point where they can safely race it.
The whining about Williams is misplaced. They are simply defending their own interests, like all businesses do.