It's true that there often exists a clash between designers and those who champion accessibility standards. IMO, this is normally because the designer in question hasn't enough experience working on software. Speaking for myself? I designed the accessibility features in Paint 3D while at Microsoft. I was in charge of accessibility of another Microsoft Studio that worked on Hololens software.
For MuseScore 4 (currently in development), I have made sure that every bit of UI passes web accessibility contrast standards and I have designed a new 'High Contrast Mode' which is being implemented right now. In addition, myself and another member of the UKAAF (Peter Jonas) have designed a far better focus state / keyboard navigation system into MS4 than MS3 had. This will enable much better screen reader support and will also help with ongoing efforts to introduce Braille support too.
I'm not one of those designers. But I do sympathise with the concern. I see it all the time!