" What if Canada did the same thing to the US? They did!"
No, they didn't. Canada tried to boost Canadian media presence on American streaming platforms.
Making sure gooby gets an international viewing is very different from transmitting information to an overtly hostile government known for cyber attacks on its international peers.
"The platform isn't a national security threat".
It's a fact that the app TikTok is based off of, Douyin, sends the private data of every user straight to bytedance, owned in powerful minority stake by the Chinese government and that tiktok did the same thing with US user data until they promised they stopped a couple years ago.
It's not some baseless concern, it's a national security consequence against data disclosures that were already carried out and have continued to this year despite assurances 2 years ago that data leaks to bytedance are not happening.
"Instrument of soft power"
Marvel movies becoming super popular internationally is an example of soft power. Gathering the personal information of users with a continuing precedent attacking US digital infrastructures and democratic institutions is not soft power, it is hostile statecraft.
I am not a proponent of monolithic tech companies nor am I particularly aligned against international competition in tech supremacy, but this ban isn't about theoretical cultural competition.
This tiktok ban is about the recent gathering of personal information that can be used to assess and attack digital infrastructures and electoral behaviors by entities that are continually attacking digital infrastructures and electoral processes, entities focused on consolidating power not within some international free market of soft cultural influence but by gathering and consolidating power and using that power to forward state ambitions.
If we wanted national data and communication security we would shut off the transatlantic cables and physically separate the U.S. Internet from the rest of the world. All matters of diplomacy could be conducted in public courts at the coastlines instead of over telephone wires and emails. Problem solved. We could set up a nice star-spangled curtain and let all the globalists rot from the fallout.
"Afraid of your neighbor's dog? Never leave your room, add a harness to your bed and strap in, wear plate armor at all times".
Not exactly practical.
There are ways to improve security without immobilizing yourself.
Blocking the widespread distribution and use of an app that sends personal and national data to a hostile government actively collecting and using that data to conduct digital and electoral attacks is not immobilizing, it's a simple step with zero downside that safeguards hundreds of millions of people.