Comment by ilikepi

It's mentioned in the article. After uninstalling the main application, you also have to kill the helper app named ZoomOpener. The article gives some Terminal commands to do this, but you should be able to find it in Activity Monitor if your more comfortable there. Once you kill ZoomOpener, remove it from the list of Login Items in System Preferences -> Users & Groups. Lastly delete the folder called .zoomus from your home directory. You can do this in Finder, but it'll be hidden by default, so you'll have to use Go -> Go to Folder... or some other trick to expose it.