It's not about the difficulty of making a replacement account. It's about the loss of profile / reputation / recognition. The longer a user has been contributing, the more painful losing all of that becomes.
I guess I never saw it that way. Personally, I don't really care for reputation / reputation. Case in point, I've been on HN for almost 2 years, and I only recognize a handful of names: patio11, edw(somenumber), tptacek and pg. Usually, I read comments without even looking at the name, unless the comment is so profound that I have to know who said it This is why those 4 stick in my mind - they have said incredibly insightful things many times - I'm sure that a) they always say what they want and b) they have enough karma to burn anyway (e.g. patio's post about SEO for which he got absolutely blasted).
