Hey, chill out......
I agree with you entirely. However; that particular part of the 172 handbook for certain versions was (I have been told) more as a result of the sales and legal folk wanting this in, rather than something that was potentially dangerous.
Not all 172s have this restriction.
Sometimes in life you have to throw the book out and do what is right at that moment.
If you read KABZ' post he was not at 200 foot. He needed to shed a 1000+
He has obviously mastered the sideslipping skill well.
QED.
From your post I gather that you have no/limited experience in slipping gliders. No recovery with engine there.
The best ones are right down to the deck with only easing off the slip and the backpressure for the flare, one fluid motion. Grand to do and grand to watch.
Not for beginners tho'
FD