You're mixing up communism and nationalization[1]. I suppose those are related concepts, but since communism ostensibly serves the working class, I'd expect to see nationalization under communism/socialism to start with things like health-care, civilian infrastructure, and agriculture, whereas under fascism (which famously also nationalizes), I'd expect the industries which help the state expand (military and military infrastructure) or control its own population (surveillance, telecom, police) to be prioritized in nationalization efforts.
I don't think the person you replied to is mixing them up, but instead, criticizing others who use "communism" as a blanket term for most any government involvement in the market.
[1]: https://en.wikipedia.org/wiki/Nationalization