Most children diseases you only get once and after that you're immune. They are most of the times harmless for children, they are way more dangerous if you get them as an adult. Vaccines don't always work on everyone so if you're not naturally immune as an adult you could be screwed. That's why parents throw these chicken pox parties so the children all get chicken pox and have it other with then and are immune.
Like I said I'm vaccinated against most things myself (though I actually had chicken pox as a kid and I'm totally not getting vaccinated against the flu - hello? It's just the flu!) - but I can also see the point of the parents. Natural immunity is always better than an immunity created by medicine. We depend on medicine way to much anyway. That's why most immune systems are crap. Of course you shouldn't bring your sick child to kindergarten or school and risk others who don't want that. But if you keep your child home until it's totally healthy again - their choice.
Like I said I'm vaccinated against most things myself (though I actually had chicken pox as a kid and I'm totally not getting vaccinated against the flu - hello? It's just the flu!) - but I can also see the point of the parents. Natural immunity is always better than an immunity created by medicine. We depend on medicine way to much anyway. That's why most immune systems are crap. Of course you shouldn't bring your sick child to kindergarten or school and risk others who don't want that. But if you keep your child home until it's totally healthy again - their choice.