First of all, I have no clue where that knee-jerk response came from.
Secondly, I cannot believe that Gruber would state that Apples quarterly report has more importance than a day that remembers a remarkable man. I think Martin Luther King JR day is pretty damn important one. But that`s just me, and my opinion.
I don't think he meant more important than the holiday itself, but more important than the fact that the markets are closed today, with respect to how Apple's stock price fares.
No--you're misreading him. When he says 'more important than the holiday' he's talking about things that impact Apple's stock price:
"The announcement of his leave was perfectly timed: on a weekday, but a holiday on which the U.S. stock market is closed
More important than the holiday, though, is that Apple announces its quarterly results tomorrow, and they’re expected to be excellent"
See, "more important than the holiday" is referencing Apple's strategy of announcing Jobs' leave on MLK day. Gruber is comparing two things that affect Apple's stock price--announcing on MLK day to avoid a panic, and announcing a day before Apple's Quarterly earnings report, and concluding that the latter tactic is more significant.
I've seen this guy write some pretty stupid things, but this takes the cake.