It's not unfair. Looking at my home studio here I have nine different MIDI synths all set up, two require adapters, and for some reason one set of these sets of identical-looking adapters doesn't even work properly on one of my synths that needs 'em. The other takes both, one only likes one pair. It's a huge pain in the ass. Other issue is they come out easily, DIN has a very solid connection and it takes quite some force to remove the connector. Also I'm not entirely sure how good the isolation is on those little 1/8" jacks, proper DIN MIDI connectors are all opto-isolated so you don't get ground loops.