The word "semite" has two definitions, one mediveal and one modern.
Palestinians are Semites according to both of them.

While yes, the specific term "anti-Semitism" was popularized by the German journalist Wilhelm Marr as an alternative to the (at the time) more common phrase Judenhaß (e.g. Jew-hatred).

Basically, he wanted a more scientific-sounding term that made it sound less like plain hatred of other people but made it seem like the supposed deficiencies of Jewish people was a byproduct of their race rather than belonging to Jewish individuals.

His use of semitism/semitic as only referring to Jewish people rather than the broader group of peoples the terms had, originally, been coined for was also in line with other Germans of both his era and the previous century (and certainly into the next century as the Nazis used these reasonings to back their more developed "race" science and world-view).

That targeting has often been retained by the word even as it's outgrown its original prejudiced purpose.

And the award for best comment goes to you. Why didn't we all think of that?

I'm being serious. Good argument.

In practice, "antisemitic" means "anti-Jewish".

It's a typo. It's supposed to say "plasticine".

No I'm pretty sure palestin is food. They're just labelling the free food.

You know who else is "glorifying" antisemite? Israel.

Oh wow, there's more of them!

It is a simple fact that the vast majority of Jewish people support the Occupation

Even if this were true, it would still be wrong to target a random Jewish person for your message about Israel. Members of a class should not be treated differently because of that class, even if the concerns of the wider class are valid. That is literally prejudice. Pre-judicial thinking, you are judging them early.

Did you do the trip to Israel thing? I had a friend in college, cool kid he was Jewish and then one summer he did that free trip to Israel thing. I don't know what kind of brain washing they do, but he comes back randomly going off about Palestinians (this was decades ago) it was like all he can talk about and if you even defended their right to exist he would go into a huge tirade.

muslims would likely prefer kosher meals as well, unless there's a specifically halal option.

The details are lacking, if this is on everyones meals, then that's ok in my books, if it only targets Jewish people then there is a problems

Way more than Jewish people order the kosher meal on a plane. You're making a bit of a leap assuming they're not Israeli. Not to mention assuming the story is real for which there's no evidence.

Why do you think that the flight crew knew that the passenger was Jewish?

You definitely can't

That's the neat part, you don't