The key to defeating gerrymandering is that gerrymandering makes votes volatile. So just a tiny shift in the political winds can undo all that gerrymandering.
Suppose in the "1. Perfect representation" option, someone in the left red column switches to blue. There would be no difference at all. There would still be two red districts, three blue ones, and blue would still win. The non-gerrymandered map is unaffected by a 2% shift (1 out of 50) in voters.
Suppose in the "2. Compact, but unfair" option, someone in the left red column switches to blue. There would be no difference at all. There would still be zero red districts, five blue ones, and blue would still win. The unfair map is unaffected by a 2% shift.
Suppose in the "3. Neither compact, nor fair" option, someone in the left red column switches to blue. Now the result is completely unpredictable. There would be two red districts, two blue districts, and a toss-up district. The winner may come down to the weather that particular day or some other normally meaningless variable. The gerrymandered map can swap winners with just a 2% shift.
Even with that highly gerrymandered option 3, only a 2% change in the vote can still let blue win. Meaning that gerrymandering could also have screwed the GOP in another way. A 2% change in voter's opinions can make the next election a landslide for democrats. What did the other thread say, oh yes, 3% of republicans are regretting their vote already.