What's the point to kindergarten if the kids have to know everything going in?

Where I live kids are expected to know their full name, age, address, colours, phone number, their alphabet, and how to count to 10, when they enter Junior Kindergarten at 4 yo, but they didnt learn sight words till Senior Kindergarten at 5 years old, or anything about vowels, consonants, capitals, etc. And they were taught those things IN Senior Kindergarten, and the parents were to support the learning with reading at home. What do the teachers there do all day- supervise the kids while they play???