It wasn't what Apple was doing that was the problem, it was the fact that they were initially quite secretive about it! People just started noticing their phones slowing down without explanation. Now days iOS tells if your battery no longer supports peak performance, which is the right thing to do.
> "Yes, they should have shipped the feature off by default and with a toggle"
Oh, it should always have been on by default. Most people would much rather their phone run a little slower than risk random crashes and shutdowns! But iOS should have told you about this from the start.