It has to do with consistency to a large degree. The concept of integrity. Would you trust someone who objects to a practice… Then does it when they think they can get away with it?
There are contradictions and times where an invalidation of a prior virtue is called for. However, someone who makes this common to their behavior is bot going to be seen as trustworthy. If I always harp on keeping your shirt ironed and never have my own shirt ironed, and excuse it as my own rules don't apply to me - then would you trust me to borrow and return a tool?
Maybe. But … If it's something expensive or that can be damaged by improper use … Maybe not.