My son currently has chickenpox and I just came upon this thread during the inevitable googling.
I have to admit that I haven't read the whole thread, and can see that the OP started it ages ago, but I can definitely see the OP's point. My son is 3.5 and goes to nursery so I knew it was only a matter of time before he got it if I chose not to go for the privately available vaccine - so, of course, I have thought about whether or not to go for the vaccine.
In the end, I had decided that I would probably vaccinate him if he hadn't had it by a certain age, mainly because it seems like it's nastier the older you get it. Which got me thinking about the current NHS stance on it: it is well-known that it is worse when older, and particularly bad for pregnant women, so it seems that by not including the vaccination in the NHS programme, they rely on pretty much everyone getting it young through exposure (and people who would suffer more than normal are eligible for the vaccination if it's medically suitable for them).
So, where has this whole taboo around chickenpox parties come from? Why is it so wrong to deliberately expose your child to something when there is a 90% chance they'll get it before they are 15 anyway, and it's much better if they do? Obviously, if you want to make sure your child is immune you can choose to vaccinate, but if too many people do this then it will actually reduce the exposure to the virus for everyone else and increase the average age of contraction, which is far less in the public interest than having it young and spreading it round your nursery (and, let's be honest, there are other childcare options available if, for whatever reason, you don't want your child to get CP at preschool age). I suspect the reason for this taboo is the same reason as for the quarantine period at nursery: it's just not socially acceptable to deliberately infect people with viruses in our current social climate, even though our NHS policy relies on it and you could argue that the obligation lies the other way.
I should clarify that I wouldn't advocate people with chickenpox going to all public places as normal, but quarantine from nursery?! It makes no sense to me, and I'm glad we have got this over with.