This is a very utilitarian way of viewing the world.

Under other philosophical frameworks, intentions do matter, not just consequences. For a deontologist, for example, thinking of Kant's categorical imperative.

My point here is that "who cares what the intentions are" is not really, at all, such an obvious thing. And there's a wealth of philosophy that's non-consequentialist. I honestly invite you to read a bit more on these kinds of ideas because they might genuinely give you a new perspective on morality.

Also, what if the viewers of the video also had their day brightened by seeing someone being nice? No wonder negativity bias is such a thing in media, not only do negative doom-and-gloom articles get more views, but positivity is actively scorned.

On a micro scale it's a nice gesture, macro wise it could be seen as inauthentic and meaningless.

There's a comparison to be made to choosing to stay in the matrix or unplug yourself from the illusion.

Because once they realize their supposed misery was exploited to make the stranger $10,000 it will probably not feel great.