Microsoft doesn't exactly like it when you crack their XBoxes and Zunes either. How is that different than Apple?
Flash (either by Macromedia, or now Adobe) has never been great. The only place it's been okay is Windows and for a long time it had poor support in OSX and little to no support in Linux (there were even mildly successful attempts at reverse engineering it to at least provide something). Flash is the holder of a fairly atrocious security record much like its new found sibling, Adobe Reader. Flash has also always had very poor video performance when compared to desktop streaming video applications and has never supported more than 2-channel audio. To utilize most of Flash's video playback features you are required to use their proprietary flv format. Where is the openness in that? I see it was conveniently not mentioned in the Adobe letter.
Apple has it's share of bullshit. The closed, guarded app store which allows religious bigot applications but not political satire is completely offensive and I will never own one of their products. Their insistence on HTML5 but only supporting their chosen audio/video formats is equally distressing. iTunes/iPod is just as poor with a lack of offering and supporting open standards audio such a FLAC.
Personally, as a web developer and off-again, on-again Linux user, I hope HTML5 succeeds with the inclusion of open audio and video standards also. I've dealt with enough poor support from the world of Flash on the development and client ends. I've dealt with the problems it's wrought upon the world of disabled web users.