The company might not have considered their request a burden (though it was -- company's mistake and author is right to be upset). Here's an example where that could be true:

My gf has a PhD in $FIELD. She always has to give a 'job talk' for every job (since I've known her that's been all of FAANG plus some non-early-stage startups -- so most of the gamut). The talk isn't that different from the post doc job talk or faculty job talk, except the content is a bit more industry focused. Of course this is a function of the kinds of jobs she looks for. Every time she's decided to change jobs she worked on her job talk first (as Jessime had done for her talks as well). And to have the audience be more than just the engineering side is consistent with that. So the hiring team may have just assumed this was a "job talk" position, and assumed that the candidate would already have it ready to go.

Clearly the company was quite wrong, and that lead to an unreasonable burden on the candidate. It's a good reason to avoid the company: if they can't get the first impression right, well, perhaps the first impression is actually accurate as to how everything else in the company is run.

Again, I'm not trying to defend this unknown company in the slightest, just trying to imagine how this kind of thing could happen. Sounds like Jessime dodged a bullet, job-wise.