Youtube, facebook, reddit, hacker news are all private organizations. They are not legally obligated to host your content (in some cases, like copyright infringement, they are legally obligated to NOT host your content).
The only thing that keeps these sites from arbitrarily censoring their users is money. If facebook deleted every article that zuckerberg disagreed with, people would eventually stop using facebook (there might be some speculation about how their "top stories" algorithm "filters" stuff out).
Less users means less ad revenue. But on the flip side, if samsung accounts for a noticeable chunk of ad revenue and that becomes at risk, less ad revenue means less ad revenue too. If blindly DMCA'ing videos yields a loss of 2% of users, but keeping the video up yields a loss of 5% of ad revenue (from samsung's share), then I imagine they will always prefer to side with samsung.
This isn't illegal, this is just one of the truths about capitalism. If a company exists to make money, it will side with money. if a company exists to provide a quality service, it will side with quality service. Quality service often doesn't have the marketing team though.