@Daaark: Let it go. Not everyone is comfortable with giving out personal information -- even a minimal amount of it -- and I think (at least after his initial posts) Khatharr has been pretty reasonable in explaining his objection and making it clear that it's just his personal preference rather than an objective problem that would affect the majority of users. This is an issue for some people, so it's not unreasonable to mention it in a discussion of Unity so that people who do care can make a more informed decision.
There's no accusation that data is being sold, misused, etc. and Khatharr isn't telling people they should never use it -- he's simply explained why he personally prefers not to use it. There are people who are uncomfortable giving their information to G-Mail as well, and if they're happy to miss out on using the service in exchange for keeping their information private then that's their own choice, and there's nothing wrong with that.
I think Unity is a great product, I don't mind having to register to use it, and I don't think that the questions asked are overly intrusive, but there's absolutely nothing wrong with someone choosing not to use the product if they feel differently.
//EDIT: To be clear, I've voted up your post because you provided useful information about what Unity use the information collected during registration for, but I've also voted up (some of) Khatharr's posts because I think he's stating a valid (if possibly minority) personal choice he's made and it's a little unfair that he should be down-voted and told this is "unreasonable". Different people are more or less comfortable than others with this sort of thing, and as long as he's not spreading mis-information or shouting from roof-tops that everyone should agree with him I don't think there's anything wrong with him briefly explaining his position -- which some other people looking for an engine to use might also share.