I am curious about the way you assess validity
The poll is on a Tesla enthusiast forum. The group you are polling is therefore inclined to be positive to Tesla, but also to have strong opinions about Tesla. Furthermore, the poll is in the subforum "Model X", which means that primarily you will be polling people who are enthusiastic about the Model X. The thread title is "How important is it for you that the 2nd row seats of the Model X are stowable?" which is pretty neutral, maybe with a slight bias. Enthusiasts will tend to care about most things posted on the forum. They might not get involved, but it costs them almost nothing to enter the thread, answer the poll and see if anything interesting is being said.
The poll question is "What do you need to not cancel your Model X reservation?" This excludes those who have clicked the thread but who do not have a reservation (They will mostly either vote "other" or not vote at all), also it angles the question such that it pushes the voters towards the milder options, as many want convenient folding/stowable seats but won't definitively say that it will stop them from buying the Model X, given that this is a car that they care so much about as to put down 5k USD or more, before even seeing the car. In this respect, the poll is conservatively biased, where the numbers for those who require flat storage space will be understated.
I think the biggest issue with the poll is the question if the people who frequent the forum are a representative sample of Model X reservation holders as a whole. I think they aren't, but it's harder to say which way they will be biased. Some non-enthusists might buy the car without caring about anything other than outward perception, others will carefully weigh capabilities up against the capabilities of other SUVs. It's impossible to say which group is most important, but what we do know is that the Model X enthusiasts, those who consider all sides of the issue until they're blue in the face, are generally negative to non-stowing seats. Overwhelmingly so.
Also, there is certainly a correlation between being a first adopter and financial resources. This forum is overrun by first adopters, and thus people here will have above average resources, even for Tesla buyers. There will be an inverse correlation between financial resources and required specifications. Less resources -> higher requirements. This is because if you have a four car garage, there's no problem having a car for every situation, but if you only have two cars, that means each car must be more capable. This means that the people on this forum can be expected to rate the need for stowable seats lower than other Model X reservation holders, when only considering finances.
There are other aspects I can discuss, but to sum up, I simply assess the validity of the poll differently.