IMHO, J street is just another form of Zionism, that uses a different tactic that appeals to a more liberal/left wing audience. In my opinion and based on my observations, J Street uses a tactic called compartmentalization. This may be deliberate, or they may do it without knowing it.
BTW, for those who don't know what J Street is I am not going to go into details here, as it is easy to find.
Back to compartmentalization. It is one of seven concepts I wrote about previously related to Zionist Psychology. So what is it:
Compartmentalization – Holding two conflicting ideas or behaviors, such as caution and incaution, rather than dealing with the anxiety evoked by considering the incautious behaviors more deeply (hypocrisy)
J Street basically holds the two conflicting ideas of supporting Israel while at the same time supporting peace. That doesn't work because the whole concept of Israel and Zionism is at odds with peace. Zionism hijacked Judaism with goals of turning Jews into warriors and occupying an area of land that was already occupied with an indifference to those already there.
But those in J Street avoid this reality, by refusing to acknowledge what Israel and Zionism actually is: most likely because doing so would produce too much anxiety and force a realization. A realization that would force them to part ways with friends and family most who will no longer accept them when they acknowledge this reality. So they just talk about an unrealistic peace that isn't going to happen as long as Israel exists, especially as it does today.
But the reality is supporting Israel is supporting genocide, killing and theft. Thus, the more hardcore Zionists tend to accept J Street members talk of peace (with an eye roll) because they know as long as they support Israel, they can keep getting away with genocide, theft and continue the apartheid.
Other posts on Zionism: