Is this recent incident with Garry connected at all with the antisemetic postcards delivered last year? I haven't been following this and thus don't know what Garry's issue with the supervisors is.
If not: This is scummy writing to connect his admittedly poor-taste comments to something worse.
Being Jewish isn’t some sort of shield that gives you special rights over anyone else.
It was brought up because they are receiving explicitly antisemitic content from the same people who loved and weaponized Tan's tweet.
A better question to ask yourself is why Jewish people seem to continually end up in this situation: on the receiving end of antisemitic abuse.
Political stuff pisses people off, but people who are pissed at Jew can always just trot out the antisemitic and dehumanizing statements... Such threatening comments have proved credible enough of the time to make the person on the receiving end really second guess about their safety.