I’m not so sure about the “no exceptions”… I assume you’re refering to the Web Accessibility Directive here. It specifically states this:
This directive does not apply to public service broadcasters or non-governmental organisations that do not provide services that are essential to the public or specifically to people with disabilities.
This is very much an exception, and a big one at that.
Since reddit does not provide services essential to the public, they are not required to comply with web accessibility standards.
I’m happy to be proven wrong here, but this is how i interpreted it and it would cause a lot of problems if the EU started going after private websites (which reddit still is, they are not a public sector, nor do they provide essential services to the public) and force them to be accessible.
philips hue (and many others) use zigbee, which means you could set up a self hosted instance of something like home assistant and get a zigbee adapter. That way you can control the zigbee lights with open source and self hosted software, and you also have the option of keeping everything entirely local if privacy is a concern