Obviously claiming that one or some Jews speak for all Jews is antisemitic but there's another issue here. It seems like only yesterday that Bibi turned up in Paris for an electioneering junket in the wake of the Charlie Hebdo attack in spite of being asked by the French president not to go. Again here's Ha'aretz:
Netanyahu: I will go to Congress like I went to Paris – to speak for all Jews
Prime minister says he will go anyplace he is invited to convey Israel's position on Iran
The man's utterly shameless.
Hollande asked Netanyahu not to attend Paris memorial march
Absence sought as part of attempt to keep Israeli-Palestinian conflict out of European show of unity; After Netanyahu insisted on coming, French made it clear Abbas would be invited as well.