Twitter actively pushes some content and hides others.
So it's controlling what people see with an editorial decision.
The fact that this decision is made by an algorithm is entirely irrelevant.
Therefore Twitter should be fully responsible for any harm caused by what it publishes, and any illegal content.
They can't claim to be just a platform as long as their algorithm controls what people get to see.

If the EU enforced this, there would be no need to ban Twitter.