It's simply because (general) you should never have gotten to the point where you are actually reading the question, the answer, and then coming to a conclusion as to whether JC was right or wrong in his response in the first place.I’m also struggling to see why anyone would follow @Charlaquin ’s advice to ignore this ruling, when it makes a lot of sense.
(General) you should have already known what your ruling was at the time someone in (general) your game tried to use Bardic Inspiration on a Dispel Magic check. (General) you should have known how Bardic Inspiration works at your table, how the Dispel Magic spell works at your table, and thus how the two of them combined together at your table... and thus it doesn't matter at all what JC ultimately says.
B. Dave Walter's question and JC's response should be nothing more than a curiosity. That's it. Giving it any other credence is to go against the central premise of 5E altogether, which is Rulings, Not Rules.