I can't speak for everyone who downvoted, but maybe allow me to share a viewpoint.
Some see the use of generative AI as simply stealing other people's hard-earned craft and talent (for the generated art) and programming skills, without even so much as credit or visibility. Plus setting the planet on fire for it, using up precious non-renewable resources, draining aquifers, endangering jobs etc. while making billionaires richer and more powerful and taking away the means of production from the common folk. Who will have to pay the powerful for compute time because they've deskilled so much they can't put together a gallery shooter game themselves anymore.
Not trying to troll or flame or anything, but what's a good tool for some is all those bad things for others. That's why any use of it gets such a negative reaction, especially in the fediverse.
Absolutely, it's also an accessibility and UX problem.
The fonts they use are too thin and frequently semitransparent (!) over a blurred and/or gradient background. So you end up with a thin light grey font on a darker grey, visually cluttered background. Unreadable if you have the slightest sight issues or if you're out in sunlight.
I was an early adopter (first batch of their first phone) and posted issues to their tracker about their font problems already 12 years ago. They never acknowledged this.
We can't fix the proprietary UI even if we knew how. The best you can do is splice your own font into the system, but that broke a bunch of UI elements when I tried. The video doesn't show it clearly, but from what I saw it looks like the situation is still as bad as it was. Back then I ended up mostly using Android apps because they didn't have that problem, they rendered with some halfway decent Roboto. If I'm just using Android apps, I don't need to buy a Jolla phone.
For a mobile phone in 2026, you need someone doing proper UX and you should have the bare minimum of accessibility features. Other systems have screen readers and voice navigation built in, etc. Sorry for the rant, it pisses me off to no end that we can't have a decent European phone and Jolla is our best chance. Maybe one day Plasma Mobile will run on more things...