Greasy Fork

Need help trying to prevent imgur from using horizontal scrolls to navigate the gallery

Imgur's default behaviour is to use the left and right arrow keys and horizontal scrolls to navigate the gallery. So, e.g., on a page like this, once the part on the right side completely loads up, arrow keys / horizontal scrolls will take you to the next / previous image in the gallery. I would like the browser to handle all these things / restore default behaviour and have been trying to disable imgur handling them. I use this script to disable focus on window load and some hotkeys across a few websites. Here is the relevant part for imgur:

else if(document.URL.indexOf("imgur") >= 0)
{   document.addEventListener('keydown', function(e) {
        if (e.keyCode == 37 || e.keyCode == 39) { //un-hijack left and right arrow keys
            e.cancelBubble = true;
            e.stopImmediatePropagation();
            return false;
        }
    return true;
    }, true);
document.addEventListener('scroll', function(e) {
        e.cancelBubble = true;
        e.stopImmediatePropagation();
        return false;
        }, true);
}

But although the arrow keys part works, the scroll part doesn't. I don't know much Javascript and most of the above code is what I made looking through Stack Overflow etc. Could somebody tell me what am I doing wrong? Also, I would like to know if there is a better / faster way to disable input elements being focused by default on page loads, since the above script can not be run any sooner than document-end.

Thanks.