Also, why would an RSS reader be a website? An application installed on your PC is superior in every way.
With a website you get shared state (these days many people are using multiple devices), platform independence and sandboxing for free. Plus custom CSS and tamper scripts for customization, browser addons, bookmarks, an API for other applications to consume the content, and probably more.
Um, no? the most popular RSS reader back when RSS readers were a thing was Google's. It was a website. And why not. Like other websites, you can log in from any device that has a browser and immediately pick up where you left off, including work machines where you aren't allowed to install native apps.
So, about that...That's how I read RSS feeds on my Kindle.
I couldn't feel more strongly in the other direction. The fewer programs running on my computer, the better. By far my preference is that "random dev code" gets placed into the strongest possible sandbox, and that's the browser.