Your guy is kind of over the top and his humor is a bit off, but he’s not wrong. A couple strategically planted trees OR a couple more carefully planned covers would provide shade to the benches most of the day.

A park I frequent has three large triangle shades suspended overhead that cover most benches and some of the play area most of the day. That’s good urban design.

This is economic design. One shade that barely covers two benches at noon.