The other person already pointed this out, but resistance against foreign occupation isn't terrorism no matter how much Western governments want it to be.
When people don't want to be slaughtered and have their resources stolen by imperial invaders it is "terrorism". When the same invaders are doing their invasions, mass murder civilians, threaten total annihilation and the like, it is "security" or "bringing democracy"...
It can be a just cause and terrorism at the same time.
For example, Nelson Mandela and others used textbook terroristic tactics to defeat the SA Apartheid regime, making them terrorists.
Whether or not the objectively just ends justify the means in the cases of South Africa, Palestine, and other oppressed is separate from whether or not the means qualify as terrorism.
For the record, I don't personally believe that terrorism is justified when there's any other way to fight back against your oppression, but am with you in not condemning the oppressed when there isn't.
Also, the military actions of Israel and the US in the Middle East are themselves textbook cases of state terrorism, which this will ALSO be an increase of.
The UK already applauded his attack. Given how Germany acted so far, i expect them to follow suit. While urging to go back to diplomacy and restraint the EU speaker also first said, Iran must not have nuclear weapons, while not saying that countries shouldn't just bomb other countries, whenever they feel like it.