:grin:
The person on ebay is pitching a sale, simple.
I shot a 22lr TC 'Match' bbl just yesterday with CCI mini mags, Rem Subsonics, and Federal Gold Targets. None of which are really match ammo and all of which worked just fine. Granted I haven't tried all brands of 22lr ammo but so far, if the chamber was clean everything worked as it should.
Note the chamber being cut a little tighter you do have to clean it more frequently than some others.
Regarding your Ruger, CB caps, shorts, longs and long rifles will work, but Ruger doesn't make a point to recommend them because they will cause the front (unfilled) portion of the cylinder to get dirty sooner than if full-length long rifles are used. If you shot 200-300 shorts one afternoon and then tried to load a lr shell without cleaning it might not chamber very easily. For me the subsonics are just as quiet as the shorts and a little more accurate, so I don't worry about it much.