Ok, maybe not KILLING, but it is making it noticeably slower.
Why do I say this?
For a long time I haven't had it installed.
For other reasons I installed it and then went back to using the machine as normal.
I would open edit pages of some remote machines I have and they were deadly slow.
If I waited long enough they would work/load, and closing the editing would also be slow.
Then I got a pop up informing me that the Moolitpass addon was slowing down the browser.
To test this, I opened `about:addons` and disabled the addon.
Went back and the pages worked as expected with little/no delay.
I shall see if I can make a video of this if needed, but just now I am working on a few other problems.
Seems it never rains: it pours! (With problems)