I'm learning how to create firefox extensions. I just started developing one to delete youtube comments.

manifest json:

{
        "name": "Comment-Blocker",
        "version": "1.1",
        "manifest_version": 2,

        "description": "Blocks comments on an youtube video by specified user",

        "content_script": [
                {
                        "matches": ["*://*.youtube.com/watch?v=*"],
                        "js": ["/commentBlocker.js"]
                }
        ],

        "browser_action": {
                "browser_style": true,
                "default_icon": {
                        "48": "/icon.png"
                },
                "default_title": "Comment Deleter",
                "default_popup": "/popup.html"
        },

        "permissions": [
                "*://www.youtube.com/watch?v=*",
                "storage",
                "activeTab"
        ]

}

commentBlocker.js:

var comments = document.getElementById("contents").getElementsByClassName("style-scope ytd-item-section-renderer");

for(i = 0; i < comments.length; i++) // length does not include reply chains
{
        var name = comments[i].querySelector('#author-text');
        if(name.href == 'https://www.youtube.com/channel/UC-CrrqEdTkOP0BD6_KQ64Uw')
        {
                comments[i].hidden = true;
        }
}

Problem is, when I load the temporary add-on the top comment is not dissapearing. When I write the instructions in console it works. What am I doing wrong?

youtube video used for testing: https://www.youtube.com/watch?v=Jk71bPz5VLo