For some reason, Google's app launcher doesn't let you remove Google services. You can add Google products, change their order, move them to the "More" section, but you can't delete them.
Helpouts was discontinued last month, but it's still included in Google's navigation menu. If you've added the Helpouts shortcut to your navigation menu, you can still click it and find that "Helpouts is no longer available."
Fortunately, there's a Chrome extension that lets you add almost any Google service to the app launcher and also remove shortcuts.