As to whether Renting hurts anyone is very much a grey area not truly clear cut. There are parts of it that do hurt the total picture and some that don't.
DVC was never meant to be a commecial business for anyone. Certainly a member that does not use their personal points and wants to rent them to friends and family is no different than the member using them for their own personal use. For one then they are renting the points, not renting reservations for peak times, there is huge difference in that. Renting only peak times, with prebooked reservations messes with the natural balance of bookings. The system was not designed to support commercial renting, it was set up to support personal use by individual members.
However when you have someone that purchases large amounts of points, never with the intention of personally using all of them and makes a business out of it, then yes it changes the situation.
For one, if you live in a residential neighborhood and suddenly one by one the homes become rental, it does affect the neighborhood. Renters, and before anyone jumps on this, not everyone is going to be the same, but generally people who rent do not have any ownership pride in the property. Why should they, they have invested nothing in the community. Disney knows this too. If rental comprises a large portion of the bookings at Disney, do you think they truly care about those guests over Members staying there or cash guests. What is in it for them? Nothing. Sure a few will become members by renting, but people who are booking prime times at bargain prices are only looking for bargains they are not looking to buy.
Renters are not going to be concerned with contacting maintenance to get things that are minor repaired during their stay as a member would. Same with the changes to Olivia's. Long time members do not like the changes, they liked it the way it was, most renters will not even notice.
I think it would be wrong to say renting hurts everyone but also wrong to say it has no effect what so ever. Everything in some way effects something else. Sometimes it is positive and sometimes not.