Could be, but I don't see any particular reason for making them softer. I have a couple of 3/4" Hamlet (brand) skew chisels and the steel is very hard in those. Don't ask me why I bought those. It was early in my woodworking and I thought you needed to have some skew chisels:). Never really used them except to play with them. I should sell them to someone who can use them.
Mike