Most Jewish Conservatives are broadly part of the Neo-Conservative movement founded by Irving Kristol and promoted people like his son Bill Kristol, editor of the Weekly Standard, and Max Boot. (There are also some well known non-Jewish NeoCons, like Condi Rice, but still the movement has always been dominated by Jewish intellectuals.)
Trump has forcefully denounced the NeoCons, starting with his humiliation of Jeb, continuing with his comments on Iraq and on to his views on international relations in general.
Also Trump has been embraced by the Alt-Right, which has an antisemitic component, and as one of it's founding principles insists on discussing forbidden topics, one of which is the role of Jewish power in our society. You see this broadly on their sites from the over-the-top Nazi clowns to intellectual efforts to understand Jewish power, such as the writings of Kevin MacDonald. This is the stuff Hillary was trying to tie around Trump's neck last night, but it really doesn't fit.
Trump's lived in the epicenter of Jewish power in the USA and successfully developed buildings and projects there for years. I don't believe that would have been possible if he were antisemitic. IN addition his daughter married a Jewish man and converted to Judaism, again not something you'd expect were he a real antisemitic person.
Finally, it's worth noting that while the NeoCons might not like Trump, he got a pretty warm reception at AIPAC earlier this year.
The movement away from Obama in 2012 by Jewish voters was pronounced. It will be interesting to see how these various factors play out in 2016, and if Trump can maintain or improve on Romney's performance among Jewish voters.
Commentary magazine was the original journal where the NeoCon ideology was formulated, so it's not that surprising that people writing for it are all anti-Trump.
It seems certain that Trump has already defeated the NeoCons in the GOP. Even if he loses the Presidency it's hard to imagine people like Bill Kristol, Max Boot, Jonah Goldberg, Mark Levin, Michael Medved, and of course Mitt Romney will ever regain anything remotely approaching the power they had in the past.
This is one reason you see many fully flipping to the Hillary camp.
Here's a list of prominent Republicans who are on record as #NeverTrump.
Meanwhile, Hillary's closest advisor is a Muslim, and she appears to be in the pay of various Islamic leaders. I'm having trouble making sense of the rationale of any Jewish Republican who would favor Hillary over Trump.