It happens but it comes down to the fact that not all life are meant to be, from poor veins to hatchlings dying during incubation we all experience it (just like we experience slugs as well) however there is no miracle wash that can prevent and save something that is not meant to be.
If mold and bacteria were such an issue people would report entire clutches lost to said issue and many breeders would do what they do.
You can lose an egg or two in a clutch and when it happen it does not mean other eggs will perish because of mold or bacteria and failure to wash them.
Here is an example 2 eggs gone bad within a few days of incubation, both had poor vein structure so it was no surprise, this picture is taken at day 56 of incubation, as you can see both have rotten yet the other eggs are totally unaffected by the mold and decay and all hatchlings emerged healthy.
So sure you can bath eggs but I can tell you that most breeders who do that for a living producing hundreds or thousands of animals do not do so. While it might work great for them with the number of inexperienced people starting to breed each year that is not something I would recommend. New people have a tendency to emulate others based on what they see or read thinking if so and so does it so can I. They try to breed small females / males because some do too and they will probably give this a try as well and because of their like of experience it will likely go wrong.
I have experience and I would not even consider washing my eggs, because to be honest I am not seeing any benefit from it. Now if they start posting official data based on a few years of using this procedure I guess people may rethink the subject, until than it's one unnecessary step .
Now wiping down an egg and using athlete foot powder or elmer glue because an egg is starting to mold because it got too wet is another issue and always worth the shot.