While that contract isn't unusual, it's not typical either, in several ways.

First off, most poly relationships don't have an explicit contract in place; negotiating rules and boundaries is standard, but putting them down on paper is uncommon, at least in part because many poly people want to change their rules as time goes on; for example, my girlfriend and I started off with quite a few rules, but we've been gradually removing those as she gets more and more comfortable with polyamory.

Second off, the contract creates a clear hierarchy, where one relationship is primary and any other relationships the two might form are necessarily less important. This is a pretty common arrangement, but far from universal.

Third, there's a bit of controversy over veto rights in the poly community; they make some people feel more secure, but others argue that if your partner won't take your preferences into account without veto power, then adding that power will only cause resentment. I lean towards the latter camp, but veto rights seem to be helpful for couples who are gradually transitioning from monogamy to polyamory, so my stance there is far from absolute.

My point is only that polyamory encompasses an incredibly broad array of relationship styles, all of which have proponents who will happily argue that theirs is the one true way.