I'm in the same camp as the author in terms of this type of copy, not only having no impact on me wanting to use the product, but also feeling it is condescending and confusing and mildly pushing me away from the product.
But I'm curious if this stuff works overall. I guess it does? People keep doing it.
At my jobs I've seen bosses decide what works based on whatever they thought is best. How much do they get feedback from real users? Never. They're the boss so they must know what's right.
I assume this is the work of one major decision-maker at Mozilla who either likes this stuff or assumes that other people do.
But I'm curious if this stuff works overall. I guess it does? People keep doing it.