Language is a funny thing. How it is interpreted is up to the listener.

Was what Stevens said a caution to USian Jews to watch their back, because some nutter may react to what "Bibi" is doing, or a threat?

Was what Piker said a threat to sympathizers of Israel, or a caution to not be overtly pro-Israel, lest some nutter come after them, because of what the Israeli government is doing?

No one's claiming that what Piker said is a threat. It's a little distressing that you don't see the difference, here. Let's take how you reformulated their statements:

Stevens: "a caution to USian Jews to watch their back, because some nutter may react to what "Bibi" is doing"
Piker: "or a caution to not be overtly pro-Israel, lest some nutter come after them, because of what the Israeli government is doing?"

Note the key distinction here. Stevens is saying that Jews need to be careful. Piker is saying that Jews should stop being overly pro-Israel. The former is fine; the latter is very much closer to blaming the victim or telling them that they are the ones who need to change themselves in response to violence.

A more extreme example would be the difference between telling a Jewish person, "Hey, antisemitism is bad right now so you should take care of yourself" and "Hey, antisemitism is bad right now, so you should maybe stop being Jewish." The former is acceptable, but the latter is just a horrible thing to tell someone.