As I said, that was probably written by someone who has no personal experience with polyamory, who may well have conflated it with other types of ethical non-monogamy such as swinging, which is about sexual relationships. Not all ethical non-monogamy is the same, but most people who don't really come from that subculture don't understand or acknowledge that. They lump it all together under one umbrella and assume it's all the same, when that isn't remotely true. One of the hallmarks of polyamory is that there are no inherent rules or structures. The intimate relationships are whatever the people involved want and co-create them to be. Ergo, they may or may not involve sex depending on what the participants desire. Mostly they do, just as most other types of intimate relationships do, but not all, which is why I wrote this OP, to bring that more into general understanding and consciousness.