Zawinul studied w/Barry Harris to get his bebop playing together. Once he did that (as much as he could/wanted to), he went his own way. I don't think he means any disrespect for Harris, (in fact, I'm nearly 100% certain that he doesn't), just that Harris' way was not going to be his way, and that the sooner he got on with doing his thing, the less time he'd be wasting.
Zawinul's never been particularly "diplomatic", but those who know him say that his heart is as big as his ego. Imo, he guy's a giant (albeit an erratic one, but that's the price you gotta pay sometimes), one of the most original voices of the last quarter of the 20th century. Like him or not, he's created a sound world that's uniquely and identifiably his and nobody else's, and he's done it with compositions that are challenging for player & listener alike, and with playing that avoids "easiness" at damn near every turn. They guy's a bad mutherfukker in my book, and to even think that he should appear "humble" towards Lincoln Center Inc. is akin to thinking that the wind should be humble towards the windshield.