It's worth noting that slippery slopes are a rhetorical fallacy[1] -- most slopes aren't slippery and most things aren't even slopes. I outlined why I think these personal views are relevant to the discussion. I don't think it's useful or necessary to lay out a general principle as to when personal views are relevant to the discussion, and I don't see any danger that Hacker News will be overrun by irrelevant discussions of someone's personal views if we continue to engage in this relevant discussion of personal views.
1) http://www.nizkor.org/features/fallacies/slippery-slope.html
Such discussion has a habit of derailing threads.
For instance, instead of talking about Urbit, we're instead mired in the finer points of one guy's murky theories on sociology.
This is not an interesting discussion on Hacker News! Racists are not exactly a rare breed, nor do the outspoken ones ever (intentional Sith absolute) bring anything interesting to the discussion.
So if someone working on an open source project were to blog, completely separately from the open source project, their personal views on, say, abortion you'd be OK with it if whenever we tried to have a discussion about that project people started discussing that contributor's views on abortion?
If not, what is the criteria for deciding what kind of unrelated personal views are OK to bring up in technical discussions?