Earlier quoted context omitted.
I've noticed the same here in NL, so this isn't just limited to the USA. You're either for Israel or you're an anti-semite. The possibility that you question the validity of the way Israel deals with Palestinians (notably: the settlements, which are in my opinion an outrageous violation of human rights against the original inhabitants) while at the same time not having anything in particular against Jews is something…
I don't think this is true in general. Many people that support Israel are critical of Israeli policies in the west bank (including the US administration). I think there's a problem when you apply different standard to Jews vs. everyone else or are parroting some narrative that has anti-semitic aspects to it. For example, I would call people contesting the right of Israel to exist, despite many generations of Israeli…
Personally, I don't think any country has the "right" to exist. Neither the Israelis nor Palestinians have any moral right to a country, and I think that the notion that "nations", which are often ahistorical fabrications, have the right to self-determination is bullshit.