It's also tremendously disrespectful to kindergarten teachers who work hard to create an environment where the students learn and develop. It's a harder job than you might think.
You also might be interested it's not just kindergarten that's important, but also pre-K that shows significant and measurable life improvements, hence the current push for universal pre-K.
(Of course I'm referring to in-person kindergarten and pre-K where tons of data exists on this.)