Several points. First, while lying or half truths are the rule with some timeshares sales system, that is not the case with DVC. By all accounts it is quite uncommon for them to clearly and purposefully mislead the buyer. Far more often than not, such issues appear to be misunderstandings on the part of the buyer. I think I can count on one hand the number of reports that seems to be a legitimate mislead over the years but I'm sure it happens. That said, one would have to prove the allegation and since it's essentially impossible to do so, it didn't happen. On top of that the buyer is responsible for their own actions including the fact that they warrant in writing that verbal representations are not binding. They are then given the legal documents of which they are responsible as well, if they (or common sense) contradicts what one thought they heard as would be the case for the 7 month window availability, that's the time to be sure before letting the cancelation window pass. Ultimately, my opinion is that one needs to be able to hold their nose and stomach the timeshare sales process to play in the game. No one is suggesting that it's OK to be sleazy but we are suggesting that sleazy happens and there's not much one can do about it without real proof.
Let me recant a personal experience with DVC. When we toured back in 1994 we were given specific information that turned out to be incorrect. Looking back it's clear the sales person either misunderstood the rules (most likely) or misunderstood what I was asking though I felt at the time I was very clear. While we ended up buying resale, we made our decision in large part based on that incorrect information (and I did have proof). DVC ended up offering to buy me out and make me whole which really was all they could do and to their credit. We ended up deciding to stick it out and we're glad we did, it's been a good run.
Specific to the OP, they're actually asking to reserve something a day before the 7 month window opens and suggested it's a sham that they can't get what they want at 7 months out. Historically they'd have had to try day by day, it's only be the last few years that the option of reserving up to 7 days at a time 7 months out was even available. The reality is that other members are getting in ahead of the OP to reserve what the OP wants. The OP also seems to be calling when online would have already been available for an hour though it's possible they tried online and then called as well, we don't know.
Ultimately we are all in competition with each other for reservations with the exception of the fixed weeks. Just today I called one of my timeshares and reserved all the best applicable weeks with the specific intent of exchanging them, part with RCI, part I'm not sure yet. In a few days I'll call Marriott and string together my weeks under the "13 month out rule" effectively reserving the highest demand weeks/resorts 15 months out. While all of these options may be distasteful to some people, they are all clearly within the rules of those systems. Those that know the rules and act on that knowledge will always do better than the rest.