Missing a test is quite easy, that's why you need to miss three before any sanction.
I may have mentioned that...
The system allows for up to three missed tests, presumably to take account of genuine no-fault cases such as this appears to be.
...but missing a test is still grounds for suspicion. It may well be easy to miss a test but as Froome rightly says, it's his responsibility to make sure he doesn't. It's a fundamental part of his job. Same goes for any athlete. Froome's excuse sounds plausible but that doesn't let him off the hook.
Rio Ferdinand was banned after missing just one test, but then his excuse was even lamer than not hearing the doorbell.
Cav missed a test in 2011 for example, to considerably less censure...
Censure? Where? The Mirror piece isn't censuring Froome and the comments in this thread have praised his attitude - especially for the stark contrast between his comments and Mo Farah's.
Gaining access to confidential information when the athlete has not actually done anything wrong.
He has done something wrong - he missed a mandatory out of competition drug test. Whether or not he has done anything wrong beyond that is a moot point.
Also your phrase "gaining access to confidential information" suggests you suspect underhand methods. I know the Mirror don't have a great track record in that department but that would be pure supposition. Unless you know their source?
The point is that wherever they got the information, they have given Froome a chance to put his side of the story and published a fair and balanced story on the back of it - and because he verified the missed test, they don't need to quote any other source. If there even was one. It is possible that it was a purely speculative question that Froome has chosen to answer candidly.