Yeah Meta is a terrible company, I don't actually believe anyone is arguing otherwise, but the point is that if they are defenderated all that will happen is that people who are on instances that defederate from them won't be able to see or interact with their content. However the inverse will not be true, so the data will still be scrapable. So if your argument for defederating is that you want data privacy then you're arguing about a moot point. You don't get data privacy either way.

Now just to be clear here, I am not saying that defederating from them is a bad idea I'm just pointing out that the argument of privacy is moot. The only way to prevent your data being scraped by facebook would be to not use activitypub at all.