How is BDS meant to work if Palestine’s economy is tied to Israel’s economy? Do they just not know that Palestinians also use the shekel?
They don't know and they don't care - but the deeper problem is that BDS isn't aimed at anything that would actually matter even if it worked.
You're right that Palestinian workers depend on access to Israeli markets, Israeli employers, and the shekel. A successful BDS campaign that seriously damaged the Israeli economy would devastate Palestinian livelihoods first.
The people pushing BDS the hardest have not thought about this because thinking about it would complicate their performance.
The one time BDS claimed a clear win - pressuring SodaStream out of its West Bank factory - about 500 Palestinian workers lost their jobs. One of them, Ala Al-Qabbani, had been earning around $1,500 a month on the line; afterwards he was selling produce from a street cart for a quarter of that. The BDS movement called the factory closure a victory. (Haaretz coverage of story)
Efficacy, though, isn't the point. BDS is a performance.
The targets it actually goes after (academic conferences, SodaStream, Airbnb) don't touch any substantial part of the Israeli economy.
The Israeli economy runs on defense exports, semiconductor fabrication, and agricultural technology. Intel, NVIDIA, and Google have R&D centers there because Israeli engineers are world-class, s-tier brilliant at what they do. You're not going to get the world to boycott a major source of its own innovation, and nobody in the BDS movement is seriously trying to make that happen. I mean...if they were sincere, they'd stop using all the Israeli technology in their phone and laptops.
The point of the performance is to cast Israel as the new South Africa*.
They know that If they repeat the same lies often enough, gullible western leftists will embrace the lie as gospel despite the overwhelming evidence to the contrary.
Apartheid South Africa was genuinely vulnerable. It was isolated, had no powerful allies, was dependent on a single major trading partner, and was economically fragile enough that any capital flight actually hurt.
None of that applies to Israel. BDS has built a tiny lever and pointed it at things that will never move. Waving the lever around dramatically is the point - not what it is purportedly supposed to do.
So when BDS 'succeeds', Palestinian workers lose jobs and Israeli tech exports are unaffected - but the participants in the western movement gets to feel like they did something. Nevermind that they themselves actually do live on stolen land and do reap the benefits of the settler-colonialists states they live in.
As usual, they're not actually interested in producing social change, they're engaged in a performance that makes them feel better about themselves.
More on BDS:
Comparison with South Africa
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*It's a variation of the "Israel are the new Nazis" schtick