THe hydrochloric acid in your stomach could lower the ph or another acid such as citric acid .
THat's what Humble is saying. He's saying that the oxygen is not important and the name stabilised oxygen is a misnomer as it isn't the oxygen that kills, it is the chlorine dioxide as it gains 5 electrons and turns into chloride.
Seriously this is the problem, people must know what they are doing with Miracle-Mineral-Supplement
Have you read Humbles sites and books? Even though the information may be flawed he is pretty much right with the chemistry.