You are right. I think you are just misinterpreting the part of the sentence ('specifically LSTMs'). LSTMs are an example of a popular type of RNN.
RNNs and CNNs are different architectures but they can be used together.

Here is another sentence with the same structure:

> It is clear than dogs, specifically corgis, and cats are very common in online memes.

[![A cat and a corgi][1]][1]


  [1]: https://i.sstatic.net/Ztt5e.jpg