UPDATED 22.11.2022
It's been two years since the last update, so here's the updated working script as per the comments below.
Thanks to BryanHaley for this.
setInterval(function () {
video = document.getElementsByTagName('ytd-playlist-video-renderer')[0];
video.querySelector('#primary button[aria-label="Action menu"]').click();
var things = document.evaluate(
'//span[contains(text(),"Remove from")]',
document,
null,
XPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
null
);
for (var i = 0; i < things.snapshotLength; i++)
{
things.snapshotItem(i).click();
}
}, 500);
Non-english users will need to change "Action menu" and "Remove from" to what YouTube uses for their localization.
I created a similar script that works by just clicking the 3 dots and then on the "Remove from playlist" button. By default, this script removes 100 videos, but that is also adjustable
This should work for all languages, so paste the script into your console and run.
YT might change their UI and you may have different screen resolution, so you may need to adjust the click x and y for each. You may also need to increase the delay if videos don't load fast enough (you can also run it multiple times).
This code prints your mouse location to the console so you can tailor the script