That's not the meaning of civilization he's using.

The Oxford Learners Dictionary you used also defines one of the meanings as

a society, its culture and its way of life during a particular period of time or in a particular part of the world

That's the definition he's using, and it's definitely genocide.

Infrastructure can't "die". He's taking about people, their culture, and everything that makes them who they are. He's not talking about bridges.

I had the same "well technically" thought at first but destroying that much infrastructure will result in some immediate deaths and mass casualties later. So maybe not technically genocide but in reality it's close.

He's referring to the Iranian civilization.