That’s literally what I was saying/implying, so I’m not sure “no” is a particularly valid response. I think you misread.

The comment chain went like this:

1. Communism can’t be a dictatorship.
2. China disagrees with 1.
3. Marx agreed with 1, i.e. Marx agreed communism can’t exist in a dictatorship.

However, Marx (and most other communist philosophers) would agree, however.