Utterly lost me at 'There’s nothing “forced” about the software update', which is true only in the narrowest, least useful sense.
This is only "forced" when you look at it from Facebook's perspective, as it'll directly impact their app, they don't control the OS version of their users. But they specifically used the loaded phrase "Forced update" to trigger an emotional response from the reader. Paints Apple as a malicious antagonist.
So the article is "correct", but not really in a useful way.
OTOH, this is more a natural side effect of how software development works than any malicious intent on Apple's part. Letting users opt into specific OS patches would be a maintaince / security nightmare.
It's not just about the slider.
...and suddenly that's a bad thing, despite the security and support advantages.
Apple can't win.
1. Don't use the offending developer's apps 2. Ignore the notifications
It really is that simple
Lovely phone you have there, be a shame if it got hacked.