If i build a shitty house and it collapses, I own it, I don’t write a manifesto about how it’s all lumber’s fault.

If you sell the house in a high-pressure sales tactic way (“buy in the next 5 min or deal is off the table”) and deny inspection to the buyer before it collapses, that would be as close as this stupid analogy can get to the JS scenario.

As does FOSS C

Nonsense. As you were told, C is not dynamically fetched and spontaneously executed upon visiting a website.

do you install linux from the source tree and build everything yourself? no, you download an .iso, so you are bound to the whims of the OS maintainer,

Nonsense. Have a look at gentoo. You absolutely can build everything from source. You can inspect it and you can also benefit from the inspection of others. Also, look into “reproduceable builds”.

Literally every JS package I’ve ever used does this.

Nonsense. The web is unavoidably littered with unpublished JS that’s dynamically fetched every time you visit the page.

they attribute buggy sites to the company, not the underlying language (rightly so)

Precisely my point. Recall what I wrote about conflict of interest. I’m not talking about a problem of the language syntax and semantics. I’m talking about JavaScript products (in the mathematical sense of a product not in the commercial sense; the code artifacts, iow).

JS runs client side and you can see what scripts are downloaded and running

That does nothing to remedy the conflict of interest. They can also push obfuscated JS but that’s beside the point. The problem is users are not going to review that code even the first time they visit a site, much less every single time due to the nature of dynamically re-fetching the code every single time you visit a page. Even if some OCD nutty user had that level of motivation, they do not benefit from the reviews of others because the code is not being reviewed from a static centralised space. Your idea that software freedom will somehow escape the conflict of interest problem is nonsense. A site admin can do whatever they want to the code to serve themselves and you end up with users running code that is designed to serve someone else.

So open source projects written in C benefit the user, but open source projects written in JS do not?

FOSS C projects hard and fast benefit the user because of the distribution of the code. We do not fetch a dynamically changing version of unreviewable unverified C code every time we visit a website. Distribution of C code is more controlled than that.

FOSS JS depends on how it’s distributed. Someone can write JS in their basement with no public oversight, license it to pass the LibreJS plugin test, and technically it’s FOSS but because of how it’s reviewed and distributed the benefits are diminishing. If the FOSS JS is in a public repo and statically downloadable (e.g. electronmail), then the conflict of interest is removed and the code is static (not fetched on-the-fly upon every execution which escapes a QA process).

Electronmail demonstrates FOSS JS that avoids the conflict of interest problem but that’s exceptional. That’s not how most JS is distributed. Most JS is distributed from a stakeholder, thus presents a conflict of interest.