This relates to paid apps with licensing. If the user pays for an app, they must be able to install it on all devices they own. The app would be free so not sure if the policy would still apply since there is no licensing, etc.
Thanks NJDude, I missed that option. Looks like I would have to uncheck 7,789 devices to do what I want. There doesn't appear to be a select all option. Maybe less if I limit to Kit Kat and the US.