If I e.g. sell SIM against Swap.Hive, how theoretically could that ever impact the Hive price?

Well, you'd be buying Swap.Hive (or HIVE as it were), correct? That puts buy-side pressure on HIVE, and buy-side pressure normally pushes price higher (as I said in the original post, this particular hypothetical probably wouldn't have much impact beyond our own internal DEX).

But, by and large, I think you've got the general idea correct, more or less, if you're focusing mainly on the downside. Since we're inside a mega-bull market in crypto, I thought it more interesting, more entertaining, and perhaps even more realistic, to be evenhanded and let optimism shine as well. 🙂