That’s not a third option in the same list (things they are going to do), it’s an item in an entirely different list (foss responses to their actions).

If you mean they shouldn't. I'd agree. But, as has been seen a lot on youtube. "They" can DMCA anything they want, and the only route out is usually to take them to court.

I mean I'd hope if they're going in this direction they will be decent about it. But, it's not the way things seem to be lately.

DMCA is a tool for suppression of free information. It doesn't require evidence that you've made a good faith effort to consider fair use or other legal complexity as it's meant to take down the information before that is settled in court, but most commonly used to suppress information from a person or group who can't afford to fight it in court. Microsoft's Github has a history of delete first without risking their own necks to stand up for obviously fraudulent takedowns much less ones with unsettled law like APIs/SDKs.