For me, there are two reasons:

One is simple marketing. "We have a product that gives you superpowers, but we have to be careful, imagine if everyone had superpowers, it would be chaos". Most people reaction would be "I don't care about the others, give me these superpowers". An then, when you finally have it, you realize it is just not that super, but the next one will be, or so they say.

The other is that established players want to build a moat. If by scare tactics, they can convince regulators to not give newcomers the same freedom they had when they started up, good for them. Bonus points if they are the ones who make the rules. They are they experts, we should follow them, right?

And yes, it is touched on in the article, it is a way to hide smaller but real problems behind bigger but hypothetical problems. When we see Skynet, we don't see the copyright problems, slop and unreliability. While they talk about the vulnerabilities the new LLM find, they don't talk about the ones it introduces in your vibe-coded app.