When using the control key whilst clicking with a track pad to right click minecraft will left click destroying block rather than placing one. This only occurs on the new launcher for mac/osx but renders survival mode impossible to play unless you're using a mouse. If this bug cannot be fixed an alternative right click control needs to be highlighted to the mac users.
Duplicate of MC-13695, please use the search function to see if your bug has already been submitted. Currently over 56% of tickets are being closed as duplicate.