Depends on your local legislation, and your company policies of allowed uses of company equipment. Some searches could violate both.
That doesn't mean undermining the public PKI to intercept encrypted Google requests isn't malicious. Possible illegality or violation of organization policy by the users doesn't vacate the malice on the part of the snoopers. It may make the snooping legal; it doesn't make it good.
Perhaps you're familiar with a little maxim about two wrongs?