Speaking from experience, as someone who's held a variety of community events/contests (nothing of the caliber of Writer's Camp, but applicable), I can see why tapas made the call they did. As the event organizers, not having it as a rule could be consider a fault of the organizer and wouldn't be fair to penalize the participant for it.
Regardless, the call for disqualification is still ultimately up to the event organizer, if they find that not disqualifying will do more harm than good. The Writer's Camp rules have a disclaimer for quality control. I don't think it should be any different for 'fairness' control if the person in question is using tactics that may not seem fair when compared to the mass of participants.
We are in an oversaturated industry. Therefore, one's marketing/promoting ability is actually essential to getting noticed. However, external promotion shouldn't be the sole reason why a person wins a contest, as community's pick nonetheless (same basis that beta1042 have already stated).
I do think a boost from friends and family is fine (heck if I could support my friends or favorite creators in a contest by subscribing, I would). But I also think that there's a difference between just a boost and the current situation. 79/115 subscribers (I am being generous by only counting the 1s) is a whooping 68 percent, an overwhelming majority.
I've done some reading around prior to even participating in the camp, and it doesn't seem like this is the first time there are issues regarding 'exploitation' of subscribers (of course most were just speculation and not verified and 'exploitation' itself is debatable). So I'm actually surprise this aspect haven't been changed yet, considering how easy (relatively) it is to exploit sub count.
I actually really appreciate that tapas doesn't dictate everything and have a community's pick, but community's pick can be really tricky to get "right". Mostly because there will never be absolute "fairness" when it comes to a popularity contest. But I do believe tapas can make it be more about the community than it currently is (granted would be more difficult to implement) by compromising with the community on how community's pick should be decided for future camps.