I'm afraid it isn't.
I found these Dew products via the Allergy UK recommendations page: https://www.allergyuk.org/our-services/allergyuk-products/?product_maker%5B%5D=456&filter-type=4
I have auto-immune disease, asthma and serious allergy. I cannot use standard household cleaning products or any air fresheners, candles etc.
I use it to spray down chopping boards and knives before washing and can use it on food prep surfaces, toilet seats, flush handles, sinks, light switches, and even soft furnishings. Anywhere I'd use normal household cleaners.
I self-catheterise and have suffered multiple UTIs over the years. Since using Dew sanitiser I've had none. I can use it on my hands, vulva and surfaces on the very rare occasion I use a public toilet.
It's helped my blepharitis and can spray it directly into and around my eyes. I dilute it 2:1 to make an oral rinse to help my mouth ulcers. It clears up any problem quicker than chemical products sold for these conditions.
I use it on my DGD's dummy when she drops it and on her toys to sanitise. I've used it on her at nappy changes with no negative skin effects. If anything, it clears nappy rash quicker than normal.
I've used it to sanitise and freshen dog bedding between washes and directly on my dog to clean wounds as it doesn't sting and won't harm her if she licks it. It quickly takes down the inflammation on any sore spots she gets.
If anyone here IS interested in buying due to the science, it does have a few downsides such as limited shelf life, no lingering effect on surfaces or skin like products such as Zoono (similar ingredients to those used in Clinell), and is quite fragile in sunlight and heat so I wouldn't leave it in the car in summer. However, it also doesn't contain alcohol so would be great for any Muslims reading.
There are many other products using this technology out there: Leucillin for pets (expensive), Clinisept+ for skin and oral health, Aquaint (for babies and sold at Boots, John Lewis etc.), Optase Protect (for eyes, sold at Boots), Natrasan (sold at Amazon). Loads more but I'm sure you could search yourself.
I use Dew products simply because their products are cheaper than those I've listed. I can also bulk buy.
A few links to counter your quackery claim (but I think the proof is in the items I've listed above and the Allergy UK endorsement):
https://en.wikipedia.org/wiki/Electrolysed_water
https://www.dermatologytimes.com/view/hypochlorous-acid-is-it-just-a-trend-
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6303114/ (this one might be of interest to people with skin problems like certain types of eczema).
Just out of curiosity and for the benefit of the OP (and others) who might want to use it, can you explain why you call it quackery?