Yes, mandatory participation was not listed as a requirement by Josh, or his sources.

But, the thing is, people like the OP are pointing at minigames and calling them parasitic... However with the definition of "can be removed with affecting the rest of the game", this covers most of FF XIV because as I said, dungeons are the only things that you couldn't get rid of.

As for sucking away form mechanics without adding anything back... There's very little of that. Most of the content exists because of the mechanics, not for them.

The biggest pile of parasitic content on a technical level is the Golden Saucer. Should the Golden Saucer be removed because it's "parasitic", or is it fine because you literally don't ever have to go there if you so choose?