[happytoexplain]

Most people either don't know there's glass or would assume the protesters don't know. And yet, even assuming universal knowledge of the glass, it's still easy to understand why people would consider this act disgusting/hateable. The message of the protesters requires digging, and even if you do the digging, the connection seems tenuous. Meanwhile, the act itself stands on its own as easily observed, and appears juvenile and pointless on its face. Regardless of opinion, it seems unrealistic to argue that people in general should feel differently about it.