Can't make map public

You need to check the box next to the green check to select it. Basically the state of the checkbox is the state of the public sharing and the green check and red X that show up are for setting or rejecting the settings change.

It is the same as is described here for the Metric Units:

https://support.dronesmadeeasy.com/hc/en-us/articles/207957693-Metric-or-Imperial-Units-Account-Profile-page