It doesn't imply "control" but, if all these people define themselves as "Jewish", then they have something in common that distinguishes them from the general p

It doesn't imply "control" but, if all these people define themselves as "Jewish", then they have something in common that distinguishes them from the general population. And unless "being Jewish" (as "being Christian", or "being Palestinian", or "being Russian") is an empty word, then "being Jewish" must have some predictive value about their beliefs, behaviours and choices. It is perfectly normal to imagine that their "being Jewish" will affect their choices more when they concern things that feel close to their identity: their religion, their culture, their ethnic group, their communities, their associations, their lobbies, and finally their Jewish State. Being over-represented in positions of power certainly allows them to exercise their free choices in directions that benefit the group and community they feel they belong to. It's that simple.