Cheeseburgers are not everywhere. I'm sitting at my desk, social media is here but cheeseburgers are not. Social media is always with me other than in the shower. Cheeseburgers are not.
Sure it's a matter of degrees but I don't see a bright line between McDonald's and tiktok. Both want me hooked on their product. Both have harmful aspects. Both have customers they know are over-indulging. Why would only tiktok be liable for that?
That's the bright line. The lack of any barrier to entry.