Uh, no. Apple SAID it was going to work, and people went out and bought them for that reason.
Then they said "oops, sorry" we can't get it to work right now and dropped the feature from their website.
So this reasoning doesn't fly. They don't have to support it, but if they don't update it then it was REALLY sh***y of them to go and say it could on their website.
Did you not read the fine print. The fine print read something like "features may be changed and/or removed...". Apple provided themselves a legal out like most companies these days do also. It did not make sense for Apple to release a feature that had serious deficiencies such as data integrity - especially for data protection. Apple tried hard for 18 months to make the TM and AirDisk work but it just wasn't possible. It may not be possible at all, so don't hang out for a fix to this issue. Move on and be happier.