Yes, it is foolish, even if like everybody else, you haven't read the TOS. I know the analogy is unfair, but it is also very foolish for young women to dress lightly, then go walk out alone in dark streets. Yet sometimes, circumstances are such that people do it anyway, and it doesn't mean they're "asking for it". Drunk after a party? Used to using "your" webmail for all your communications?
People often do foolish things, it doesn't mean other people have a moral right to take advantage of them. (Alas, they sometimes have the legal right.)
By the way, in this case, it seems Microsoft spied on the blogger's account, to know where the leak came from. The leaker may not have used hotmail at all. While it's easy to notice cloud spying when sending from a webmail, it is a bit less easy when you send to a webmail: you're not even legally expected to have read the TOS. I mean, you still have to be careless to make that blunder, just less so.
People often do foolish things, it doesn't mean other people have a moral right to take advantage of them. (Alas, they sometimes have the legal right.)
By the way, in this case, it seems Microsoft spied on the blogger's account, to know where the leak came from. The leaker may not have used hotmail at all. While it's easy to notice cloud spying when sending from a webmail, it is a bit less easy when you send to a webmail: you're not even legally expected to have read the TOS. I mean, you still have to be careless to make that blunder, just less so.