It sounds like you are intentionally misunderstanding...

Under capitalism, you are the cow, the milk is your surplus value.

The main difference is that my cows get free healthcare, food, shelter etc. instead of money to spend on healthcare food and shelter.

You don't own the cows the cows represent people.

Capitalists exploit people the same way that farmers exploit livestock like dairy cows or egg laying chickens. The milk and eggs is their surplus value.