I really don't believe this to be true! If it were know to crack easy, I really don't think Hearthstone, Woodstock and Tulikivi would have been so successful. Just to name a few.As for the cracking easy, I guess it all depends
People have been making masonry heaters, stoves, and pizza Ovens out of soapstone for a very long time. What about the soapstone bricks inside of a Hearthstone stove? They hold up to the heat and the impact from logs being thrown in.