A characteristic of communities with lots of people that do not have a theoretical background. JS, PHP, jQuery, some parts of Ruby/Python -- they defend it with their life, and I argue it's because the rest of the world looks very scary to them.
I think this really seems to stem from a "I'm only used to jQuery, anything else is a big mental effort to learn and I'd rather stick with what I know".
I get it. Vanilla JS, if you're not used to it, is scary. But if you're advocating for jQuery "for simple interactions", and assuming it's simpler than vanilla JS, at some point you should ask yourself if you're just letting your skills stagnate, and staying stuck in the past. You owe it to yourself to update your skillset. If you decide you still need jQuery (e.g. maybe you need a plugin/library that requires jQuery), then fine. But at least you'll be making an informed decision, not a FUD-driven one.
Handcrafting JavaScript applications without jQuery is possible, the real question though is: is it convenient if you like and find productive using jQuery? Here's a fact: you can always remove jQuery later when the product is mature and standards understood and there is time budget for it.
The point seems to be that you don't even need that any more, so just get rid of it. Not sure why people latch onto cruft so much and defend its continued use.
On the performance side they cite 10 percent improvement, which doesn't sound like much to a lot of people. But remember that performance gains/regressions get compounded. Maybe there are 8 things that each eat 10 percent - you either start improving somewhere or you just refuse to even try. If I could improve 10 percent while removing a dependency I'd be all over that.