The example given mentions voting for parties, but doesn't give explicit indication how this works. Are the votes directly for parties or for candidates from those parties? It doesn't say. I suspect that you see it as explicitly talking about votes directly for parties, but I see it leaving it undefined.

But really, what exactly the original example intended to convey is a pointless pedantic argument I'm not getting into.

The crucial point is that you absolutely can have multi-member proportional districts where you vote for specific candidates. So to someone who advocated for a such multi-member districts, the contention that you have to give up voting for individual candidates simply isn't true.