Regular does not mean that it is allowed to rent a single reservation.
Regular means consistent, or routine, or in a pattern. Even renting once a year but doing it year in and year out would constitute "regular' by definition of the word and could get an owner on the
DVC radar (although I doubt it from a practical, real-world perspective, but words do have meaning and are chosen based on that meaning).
Anyway, you've now gone from "It clearly reads to me that using a third party is 100%
allowed, just not
encouraged or endorsed" to
"It is only when you rent (or try to rent aka advertise) too much that you will be put on DVC/Disney's radar". If something is 100% allowed, by definition there can be no restrictions or limitations (the whole 100% thing). If there are restrictions or limitations, then it's clearly not "100% acceptable" (or, at best 100% acceptable, but only once or twice).
There are limitations (albeit the ambiguous "regularly"), and I'd wager there are enough owners who use the rental brokers for far more than one or two rentals here and there, and THOSE owners will be dissuaded from using the brokers. I'd also wager that those folks are a robust portion of the broker's book of business (and let's not forget the brokers who are flipping contracts and renting points out on them). I'd also guess the number of reservations the brokers list themselves are probably greater than one or two.
Again, as with so many posts on here, no one has or is saying that the first offense will lead to damnation and ruination. No one has said that the casual renter or the owner who likes to make multiple reservations FOR THEMSELVES will suddenly become the target for Disney's wrath. What I AM saying is that people can't just read the parts they like or assume a rule couldn't possibly apply to them, just because that would affect the specific way they use their points. Also, recognizing that a rule might exist, but convincing yourself that even though the rule sounds like it applies to you, there's no way you're a bad enough "offender" to be negatively impacted is a rather tenuous approach to things.