I think this kind of thing should happen in most units. It's not that he has to find fault with you. But as a person, this is his work instinct. He just wants to reduce the operating cost of the whole company, so as to improve the company's income. Moreover, the salary he deducted from you has not yet been put into his pocket, so this is one of their jobs.

First of all, the most direct reason is that the leader arranged for him to do so. After all, as a person in a company, he really doesn't have that much right to deduct your salary without permission. If he deducts your salary privately, it is likely that he has a very close relationship with his boss, or that he runs a company, or that he doesn't want to work. So generally speaking, these are some instructions from the boss. She has no courage and qualification to move your salary.

Secondly, the responsibility of personnel is to reduce costs. As a personnel, your most direct impression of him may be that he is responsible for all the assessments and all the forms. Actually, it's true. Only when he has mastered these materials can he know where to deduct your salary. This sounds really irritating, but if he doesn't do these jobs well, the next person to be laid off may be personnel.

Finally, the company's salary system. Maybe you will find that many companies don't have so many reward systems, but there are many punishment systems. In fact, all companies do this. After all, if you know what behavior may deduct your salary, you will try to finish the work better.