And it came to pass, when he began to reign, as soon as he sat on his throne, that he slew all the house of Baasha: he left him not one that pisseth against a wall, neither of his kinsfolks, nor of his friends. (1 Kings 16:11)
These words indicate measures of unusual severity. Not only were all members of the royal family extirpated, but all friends as well, including, probably, the counselors and officers of state. It is not surprising that the nation did not take kindly to such a king, particularly not Omri, who, as an army officer in the service of the former king, would have reason to fear for his own safety. Those who endanger others endanger themselves.