Ten-year-olds understand quite a lot of things. They don’t always think before they act, but they would absolutely understand this object lesson.
It’s water. It’s not harmful. Getting splashed with water is most ten-year-olds’ idea of a good time in most scenarios.
Is this the most constructive way to go about teaching a kid how to behave properly? No.
Is this going to scar the average kid for life? Also no.
The current Democratic party is basically the Reagan Republicans with more emphasis on civil rights.
US politics have skewed further and further rightward for the last 50 years. On a global scale, Democrats are firmly center-right.
Bernie Sanders and AOC are barely left of center for the rest of the world, but in US politics they’re “off the deep end.”