However, there are numerous state and federal laws that make trespass illegal. Noone would consent to their homes being entered by strangers who just wanted to look around. Breaking into a computer system is the technicalogical version of trespass. A hacker would say that no harm is done when they break into a computer system. I would argue that as intangible as the harm may seem, harm is done.
People have a certain expectation of privacy.
When that sense of privacy is taken away, a person loses something that though it may be intangible, is priceless. I would also question the hacker's statements that they do not harm files when they gain access. A hacker will often edit system files to cover his tracks and erase evidence of his entering the system. Also, a hacker may brag about his exploits. This could tempt other people who may not be so unwilling to steal information or change files to try access the system.