Why are business managers more hostile, grandiose and self-important than owners?

Why are business managers more hostile, grandiose, self-important, and --at times-- toxic than owners?

When it comes to businesses -- from what I've seen-- business managers act more negatively, outrageous, and controlling than their employers --even if their employers are similar in behavior. They act more cruel to employees, clients, customers, and co-workers, act as if the business is their own versus the owners, and seem to do so with reckless abandon.

I've --in the past-- heard them say things like they don't care if the business suffers due to their behavior. as long as they still get paid their standard wages. So --in other words-- they don't care if the business sees a drop in sales, income, revenue, reputation, incurs lawsuits, or gets inundated with complaints --as long the business owner will suffer the consequences, and they don't personally feel any long or short term effects of them and still receive their standard pay provided it isn't consciously disrupted or cut off.

Do they behave that way due to lack of supervision? Instructions to take on those personality characteristics? General lack of empathy? Is the average business manager just someone as mentioned? The characteristics mentioned are inherent to their type of person?