Foreign adversaries have learned exactly how to weaponize our free and open internet against our own people. Regardless of the fact that our kids are most vulnerable, China's seemingly made a point of outsourcing their most polarizing algorithmic decisions to the rest of the world but not to their own population, which is essentially a tacit admission of their awareness of the dangers of social media to their own people.
At this point, I'd venture that politicians in the US are trying to grasp at whatever they can to mitigate the risk while still maintaining their election chances. Easier to "blame China" and get re-elected than it is to dump on their own constituents for not monitoring their kids' social media habits.
And frankly, I'm okay with that. Even if a parent does their best, there'll be second-hand influences through all the kids raised irresponsibly through their parents, and nothing can be done about that aside from homeschooling or going off-grid, which is unsustainable for nearly everyone.
I'm fine with a combination of the bill introduced + bills like the one passed in Utah placing curfews on kids since parents have proven to be so bad at parenting their own kids as to present the nation with an emergent aggregate risk to national security.