Just run the game from Applications folder. If you get some error in Origin after 7th step, like “Well, that didn’t go as planned” – ignore it and continue to the next step.
So here’s how you should install DLC Unlocker (for now at least, until EA fixes their shit): So if you have automatic Origin updates enabled – you can’t use DLC Unlocker, because on each Origin launch it updates and removes the Unlocker.
As the DLC Unlocker instructions say, you have to install it again after each Origin update. You restart Origin to update it – and it still says there’s a new update. You update Origin and it tells you there’s a new update. EA fucked up and Origin on Mac is stuck in an update loop.