Leaving so many Steam groups, anyone able to help me remove this one?

Thanks then. Hadn't tried without the name myself, thought that had to be there.

Nice for it to finally be gone. :)

Chrome console returns "undefined" error if I paste the code directly in. I have to add a link with the script for it to work.

IIRC it was because they were heavily involved in keys-for-greenlight-votes, which Valve frowned on. They don't do that anymore, of course.

As already mentioned, keys for Greenlight votes. At the time of group creation, there was no rule against it, but Valve later added one and that group was closed. It still exist as other groups, and has it's own website.

Since the previous solution is no longer working I came up with my own. It's not as nice looking and simple as the previous one, but it works ;)

Group id of the group you're trying to leave is: 103582791438197174
Go to the main page of some other public group you're in. Right click the "Leave group" link and choose "Inspect element". Unfold the line above the selection, which starts with

<form method="POST" id="leave_group_form"

There you will find a line like that:

<input name="groupId" value="103582791429526392" type="hidden">

Change the "value" parameter to the group id of the group you're trying to leave and then click the "Leave group" button. If you've done it right you'll still be in the group from the group page you were at and only leave the group you wanted to leave :)

I haven't done it myself however I think what they're trying to say is that you go to the steam page and you log in and navigate to the groups page, and on that page you press ctrl + shift + I ( which brings up the inspector on google chrome up) , you click on console in the top right, and you type in that command they give you, with the group name in there. Not sure if this will work but hopefully this gives you some hints and solves your problem.

That seems to be the first solution by osttw, the second apparently doesn't work anymore and the third might work by pietruszek where you go to the main page of any other group you are in, and you right click and inspect element( which brings up the inspector again), and then you edit the values of the leave button link to have the id of the group you are trying to leave not the group of the page you went to, the one that got deleted, someone pointed how to find the id of a deleted group. Basically you're going to group 1 which you are in, and inspecting the leave button even tho you don't wanna leave group 1, but you edit the leave group button of group 1 to have the values of group 2, which is the group you are trying to leave, and so when you send that data it leaves group 2, even tho you are on the page of group 1, because the id you sent is of group 2.

I should mention all of this is done on google chrome I don't think they'd use anything else, but unfortunately you'll have to follow those prompts and deal with the inspector. If you get stuck let me know what you tried or where you got stuck and I'll try it out with one of my groups and see if I can make it work.

If you're using Tampermokey, maybe you can try this script: https://greasyfork.org/en/scripts/391660-steam-community-leave-banned-groups