Should swimming lessons be mandatory in schools?

Boilermaker21 (Expat in China)

There are swimming lessons in my city, but I was very disappointed in how they were taught. The kids spent 45 minutes of the one hour lesson practicing strokes ON DRY LAND. They only spent 15 minutes in the water. All of the children panicked and sank immediately to the bottom. Then all of the parents berated the children, telling them that they weren't paying attention to the teacher and that they were failures. I removed my kids from the lessons and taught them on my own.