To clarify, the text was not from OP's post, but from the other similar ones I found while searching. The one in the OP, "Reported antisemitism, lost my friends," was devoid of any context at all at time of posting. It does look like the Redditor posted more, I just saw and am about to go through, and will report back if there's anything interesting.

Alright, nothing super interesting, but about what I figured. Also, interestingly, this first comment is shadowbanned on Reddit; it shows on Reddit-OP's profile, but not in the thread. Anyway, as I said, about what I figured:

Lots of building comments about genocide and ‘there only being one right side to be on’. People with free Palestine stickers on their phones, wearing watermelon necklaces. The breaking point was at a work event which was catered by a Jewish company (I work in a very Jewish area), and people were making comments about the food. A senior member of staff then tried to block a training by a Jewish charity on domestic violence in orthodox communities, which is very relevant to my work. That was my breaking point.

So, as I completely predicted, it's people who don't like what Israel is doing, and feel bad for the Palestinians. And, yeah, wouldn't be surprised if they were retarded leftists, too.

Also, not sure about that last bit, and would need more context. I doubt management tried to block some Jewish event because it was Jewish.

Another comment:

My senior management have taken it very seriously and have from the start (my service is quite Muslim and Jew heavy, so they addressed it at the beginning). The individuals have had formal meetings and this is why I’m now being outcast. And someone said above I didn’t lose friends, I lost the idea of friends. Which is so true. It’s just lonely.

So, yup; wrote his "friends" up for not wanting Israel to bomb the shit out of civilians, and they got pulled in by management.

What a bunch of losers.