I don't know if this answer will be useful to you, but my experience is as such. I have seen debates over miracles in the past, and I can attest to you that no matter how much evidence you present to unbelievers, if they are truly ideologicaly invested in maintaining a particular worldview, they will not believe.
You said that extraordinary claims require extraordinary evidence. But people may think of such claims as so extraordinary, that there is no amount of evidence that will suffice to meet the "extraordinary" criterium.
Or, as Thomas Aquinas would say: To a believer no amount of evidence is neccessary. To an unbeliever, no amount of evidence is suficient.
So, what could make a majority of the population not believe in such supernatural claims? You would have to create a strong incentive for people not to believe in demons or werewolves. If people would lose something that they thought of dearly by believing in demons or werewolves, they would rationalize away every evidence for demons or werewolves.
For example (and just an example) are people transformed into werewolves by engaging on a particular behaviour that is very popular and pleasurous? Or are demons spawned by a human activity that is also at the center of economic well-being of the community? Then they have a lot of their personal emotions invested in werewolves being false! There would soon be blogs dedicated to disproving the existence of werewolves... Propagandists don't exactly prime for adherence to the truth of facts, they simply filter what they want and leave the rest.
Also, most of these Internet people are technology savvy. Today's technology allows us to create amazing special effects. Just look at the movies. Those bloggers would surely be able to replicate false videos of demons and werewolves fighting, with much more quality than a tremulous smartphone video filmed by a nervous person that suddendly finds such a supernatural fight beneath their balcony. They would say: "See? It is easy to make such videos. The original one must be a fake"
As soon as such apologetic blogs were in place, their posts would disseminate via social networks. As soon as it is shared by thousands and millions of users, there would be no way to stop it. If people were inclined to disbelieving demons and werewolves, they would share it without hesitation.
People rarely consult primary sources. If the incentive to disbelieving demons and werewolves would be too strong, people wouldn't even care to see the original video, they would just share the refutation.
There is another possibility. Maybe the general public wouldn't have a great incentive to disbelieve demons and werewolves... but the elites would have. The government or the corporations might think that belief in demons or werewolves would create a disturbance on the election cycle or on the cash flow... and would do everything on their power to disprove it.
If they had influence on the media, their job would be easily done. Instead of apologists, you would have pundits, with an aura of respectability. People would be bombarded with refutations left and right. The government could even use the education system to imbue children from an early age to discount everything supernatural.
Again, people seldom consult primary sources. They would prefer the media version. And the version that they are more comfortable with, according to their worldview.
Even if people did go see the video, they might do it just as a curiosity, but with no intention of believing in the video, no matter how convincing it might be at first glance. If you see a fiction movie, you will not believe it, no matter how good the special effects.
Conclusion: Would the majority of the population dismiss it as a hoax? It depends! Depends on the amount of motivation of the population to dismiss it as a hoax. It depends on the a priori general perception of the population regarding the supernatural. It depends on the influence of the anti-supernatural opinion-makers. If such conditions are met, rest assured, that the majority of the population would dismiss it.