Terms like radical, extremist, and left/right are all relative to a center, but that center is not fixed or objectively determined: it is itself an object of contestation. The way the game works is that everyone strives to define his/her own position as the central one and relegate opponents to the extremes, the unquestioned assumption being that centrism (also called moderation) is good while extremism is bad.
Applying this model to the case under discussion, the right-wing Zionists, who in the past, during the ascendancy of Labor Zionism, were condemned as extremists, now demand to be treated as the center, with the result that forces formerly classified as centrist are now redefined as extreme. Especially strict requirements are set for Palestinians formerly labeled as centrist and moderate: basically, while in the past it sufficed for them to accept an accommodation with Zionism solely on pragmatic grounds, they must now support Zionism even in principle. Otherwise they are banished to the outer darkness of radicalism and extremism as ‘de-legitimizers.’
I think that all those stigmatized as radicals or extremists, instead of playing the game and desperately insisting on being treated as centrists, should reject all these arbitrary labels and expose the game itself and the goals of the people who try to make us play it.