That's coz it's not your neighborhood, in the property ownership sense.
edit: Albeit, thanks for making that point, which exactly clarifies the reason why someone might say a ridiculous phrase such as "I support strictly voluntary segregation": to later on contradict 'emselves a bit and complain about the lack of freedom to impose segregation on those who don't want it. Likewise, the "strictly voluntary eugenics" quickly comes down to someone's volition to neuter someone else.
By analogy: Private property also includes (must include, in my opinion) the freedom to "impose" it on those who don't want it - If Alice has a bicycle which she considers to be her private property and Bob tries to take the bicycle because Bob doesn't believe in private property and doesn't respect the notion of "Alice's bicycle" in the first place, I'm damn well going to side with Alice in telling Bob to go away, and if necessary, threatening violence against Bob.
If you try to form a concept of "strictly voluntary private propert...
A long blog post explains why the author, a feminist, is not comfortable with the rationalist community despite thinking it is "super cool and interesting". It's directed specifically at Yvain, but it's probably general enough to be of some interest here.
http://apophemi.wordpress.com/2014/01/04/why-im-not-on-the-rationalist-masterlist/
I'm not sure if I can summarize this fairly but the main thrust seems to be that we are overly willing to entertain offensive/taboo/hurtful ideas and this drives off many types of people. Here's a quote:
The author perceives a link between LW type open discourse and danger to minority groups. I'm not sure whether that's true or not. Take race. Many LWers are willing to entertain ideas about the existence and possible importance of average group differences in psychological traits. So, maybe LWers are racists. But they're racists who continually obsess over optimizing their philanthropic contributions to African charities. So, maybe not racists in a dangerous way?
An overly rosy view, perhaps, and I don't want to deny the reality of the blogger's experience. Clearly, the person is intelligent and attracted to some aspects of LW discourse while turned off by other aspects.