Here it seems the JS code can fetch data from any domain:
https://github.com/kaangiray26/geddit-app/blob/main/src/js/g...
Since that is not possible in the browser, is that something Capacitor provides?
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS
So usually it does not work in the browser.
Try this in your console while not on Reddit:
fetch('https://www.reddit.com/.json')
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS