I have no idea how a variety of clergy and diocesan addresses, plus most of the churchwardens north of Ipswich all got marked as "spammers" by Hotmail.
Probably one of them, or someone else using the same server, is a spambot, so one of the blacklist services that hotmail checks with is blacklisting the entire server.
As for data mining, that could apply to ANY mail scheme
Not one where you run your own server. And not very likely for those of us who pay for email service from a hosting company - their business is renting hardware and bandwidth, not snooping on their customers' traffic