Raw icon names (that you cannot influence) often don't make a good replacement for proper alt text. Quite often they should not be read out at all. Furthermore, people forcing websites to use a font like OpenDyslexic will see these non-descriptive icon names instead of the real icons.

Just to complement other's responses, accessibility is a spectrum.

We ought to believe someone chooses to use an icon for aesthetics AND usability reasons. If the icon can't be rendered at all, it defeats it's purpose despite it having a "description".

Ultimately, if a well designed, user-friendly system doesn't work the way it's intended to, it is an accessibility issue of some degree. Albeit, some times more trivial than others.

The content "trending_up" is almost useless, a voiceover will not interpret the underscore as a space.

There are no ARIA attributes that link any of the text to the buttons.