It usually wasn't necessary because oftentimes your kindergarten class served this function. But yes, pre-vaccine, parents wanted their kids to get chickenpox during childhood because it's a much more severe illness if you get it as an adult.
𝚁𝚊𝚢𝟶𝚏𝚂𝚞𝚗𝚜𝚑𝚒𝚗𝚎🇺🇦✊Wasn’t chicken pox the one they got the kids together to “party” and get them over with?