According to the article the attack came from an Iranian IP address. Well ...

Suppose it wasn't a false flag operation. Why would Iran threaten the EU when the EU was skeptical about the war early this year and suffers from it due to lack of Qatari LNG?

The logical step would be to do diplomatic outreach to the EU.

Now the EU has a casus belli (more like supporting the war rather than participating). It all sounds like the EU is selling the war to its population, but maybe Iran is really that stupid.