> Is "talking points" just a roundabout way to summarily dismiss the opposition's arguments and imply they're dumb/misguided?

It is. I've read dozens of comments like this on HN, and repeatedly see the "it's incredible that...", "talking points"/"propaganda", and "wow look at how much bad stuff there is in this thread"/"I'm so disappointed in HN" memes, and every single time it's because the author is trying to dismiss the opposition's arguments without responding to them individually and actually addressing their points.

This kind of thing clearly fits into the "sneering" category of things that aren't allowed on HN and so is valid for flagging. I do it and I highly encourage anyone else to do it who wants to preserve the culture of HN.