although well meaning, it sounds a bit irrelevant. Something in argentina about what people can speak about regarding israel. It isn't going to make much difference. Maybe I Have the wrong attitude there. But anyhow..
jews in particular are very diverse, no individual can really speak for jews.
infact, even a tony blair or a george bush , would be considered by many to be not speaking for their respective countries!
just becuase somebody is british it doesn't qualify them to speak for britain.
similarly if jewish..
or even within any group.
I suppose a person if he is the leader, could speak for his party. And members have him as their spokesperson. For example, rabbi kahane spoke for kahanists.
a person can speak for an organisation. that's for sure. And an organisation can have members, that show their consent by joining or retracting their membership.