I call nonsense to the nonsense conclusion.
Also, I said we'd need to look at the data more deeply, but it's not even CLOSE. And I stand by it.
After thinking about it for a bit, no hitters usually happen when the pitcher is having a very special day. He's just in the zone. It's that human thing we have no control of. Some days we're good, and some days we're crap.
But the moment you bring another pitcher in, the chances of him being in that unhittable magic zone are less likely. And the more pitchers you bring in, the odds lessen more that they'll all be in the zone.