Dettol, Persil,
Along with other laundry sanitizers have been around for ages, indeed commercial laundries have had access to "quat" based anti-bacterial laundry rinses for years.
One primary use was for female undergarments after a bout of yeast or other infections. With many such things now made wholly or in part of synthetic fibers the old fashioned "boil washes" aren't an option. Indeed for yeast such a process wouldn't do much good as spores can withstand boiling. You really need to use an autoclave in order to get at them.
You rarely saw such products in the United States (Lysol had one such offering years ago, it came in a white box), because Americans then to use LCB in vast amounts. Chlorine bleach will kill just about anything (including mold/yeast spores) on laundry, to that is that.
Commercial laundries would use these anti-bacterial rinses for towels, sheets and perhaps cloth diapers. First as a measure of hygiene especially if LCB and or very hot washes were not done, and also as means of keeping freshly laundered linen free of a whiff of stale or other odors that may come during storage.
Many powdered detergents contained various disinfecting/sanitizing chemicals historically. The old Surf formula actually had a patented antibacterial/deodorant chemical mix which was behind it's claim to deal with stinky laundry. By incorporating various chemicals such as phenol you can achieve a pretty decent rate of germ knock down in laundry. Alkaline pH levels, hot water and strong agitation all will deal with germs on laundry as well. In some cases all you are doing is sending the bugs down the drain alive, but still they are off the laundry and that is what matters. Machine drying at high temps and or ironing further renders laundry sanitized.
Problem today is many households are using liquid detergents that do not contain bleaching agents, and low wash temperatures. This can lead to a build-up of gunk not only inside the washing machine but *germs* on laundry.
Now one has said this before, there are few if any cases of anyone becoming ill from laundry. Even when such things have happened it was from handling soiled laundry especially contaminated by being in contact with an ill person (smallpox, that sort of thing). Long as one has a healthy immune system, intact skin and exercise proper precautions there isn't anything much to fear from "clean" laundry, even if it hasn't been boil washed to death with strong detergents.
However if there has been an outbreak of a stomach bug, yeast infections (jock itch, athlete's foot, etc...) then you *might* want to consider using a sanitizing laundry rinse.