If someone showed up at your house and told you that your water could kill because of some microbe you have never heard of that they claim is getting into your pipes and the only way to make yourself safe is to install this helpful filter that they are selling would you believe them?
A /. reader probably not, but the general public ?
If there was any profit in it, you could easily create a scare campaign about DHMO which could turn very messy. People can be insanely gullible when you present things the right way.