Because Shou Zi Chew answers to the PRC which is a geopolitical adversary of the country the average citizen is able to democratically determine the direction of.
Ellison, Zuckerberg, and Shou Zi Chew (who to be clear is only the CEO of TikTok, not ByteDance) may be willing to brainrot Americans, but it's for the sake of profit, so they can be pressured to change. Facebook and Twitter cooperated with American intelligence to uncover to Russia's disinformation campaign and they have no incentivize to fake compliance.
From those investigations, it was revealed that Russia and likely other foreign adversaries do simply want to brainrot Americans for the sake of destabilizing the country. If TikTok gets investigated for Chinese intererfence, China can pressure Bytedance into sabotaging these investigations.
Ellison, Zuckerberg, and moreover Elon Musk have all contributed to Trump's rise, which has seemed fairly destabilizing for the United States. Their profit motive comes at our expense as well.
