I agree with everything mostly but this. CHD (Chlorhexidine Diacetate) the principal component is de-activated by organic materials so the humidifier would need to be new and cleaned daily or more. It also is reckless advise, CHD changes with heat (not all humidifiers are cool) to become quite toxic. Your points around drugs follow true for disinfectants CHD/CHG both are sensitive to organic material and have relatively poor stability. You have suggested a method that would create resistant bacterium as well. A deactivated disinfectant is not going to do anything else. Like you I cry against misuse/incorrect use, of in my case disinfectants, and sadly there are more whom mis-use disinfectants than correctly use them.
http://www.vetdepot.com/product-labels/nolvasan-s.pdf
How exactly is F10 more 'harsh' than CHD?
CHD MSDS has far more cautions than that of F10. F10 is basically stable and does not have any hazardous decomposition products. For that matter any condition or state or exposure that makes it a hazard. CHD does for both. F10 if mixed with strong alkalis, may neutralize or reduce disinfectant qualities, and is an irritant if in eyes and ingested. CHD may release toxic vapours when subjected to heat, may be harmful if swallowed, and medical advise should be obtained if you get it in your eyes. It is hard to say F10 is harsh compared with CHD/G.