The "hard" was between quotation marks for a reason, as I meant to point out the difference between removing some light contamination on a touch up or do a full claying on paint that has a lot of contamination. It wasn't directed to how much pressure you put on the clay...
I agree that it could degrade the sealant layer and that it's advisable to put on an extra coat after claying, but you're not starting from scratch when you do some claying to remove some light contamination.
The reason the difference from 'starting from scratch' and 'putting a coat of sealant on' after claying might sound like semantics to you but not to me, can be explained in one word: Zaino.
Different products might have different results, but because we all know how much work it would be to start from scratch using Zaino, I'm happy I don't have to do that every time...
