Not necessarily

In medical malpractice the doctor does not have to be intentional or reckless to be held libale. Malpractice originated from negligence so that a gross neligence would suffice. Ordinary negligence is permitted since docters are human beings and human beings all make mistakes. The key issue is the standard of care. If the doctor is deviating from the common practice in his field, he will liable for all injuries resulted. Take attorney malpractice for example. Some lawyers are very incompetent. They can mis-identify issues and mis-use applicable laws, not necessarily intentional or reckless, but they are still liable.

Now in the home inspector case, the key is whether the defect was so obvious that a reasonably prudent inspector would not miss. If so, he is liable. Of course, if he was intentional or reckless he will be liable definitely.