Oh god you do love the sound of your own clacking keyboard Deutscher! You are correct in some of your assumptions, you are totally wrong on others. I have no reason to doubt Shane Simpson, Danny Brown (who had his entire 70 snake collection wiped out as a result of introducing infected breeding loan animals into his collection) and his colleagues, just as I don't doubt the work of Tim Hyndman, the researcher at Murdoch Uni in Perth who has done 10 years' work on these viruses. All of these individuals have far more exposure to the trade than you do, unless you've added a BVSc to your incredibly long list of academic achievements... These people know the risks beyond your anecdotal claptrap. I suggest you ring Shane Simpson about how often he sees infected snakes in his practice, if you think viral pathogen problems are "very very rare." It's a simple fact that in most cases if a pet snake dies, the owner rarely takes the dead snake to the vet for an expensive post mortem and pathology work - who is going to spend $400 or more on a dead snake that cost them $100 to begin with?
Of course we all know that few people, if any, quarantine their new arrivals effectively. Of course pet shops and expos have people handling animals indiscriminately, and of course there are some risks in everything we do with our reptiles. Sellers at expos who are serious about the health of their animals NEVER let other people handle their animals at the venue. To be honest, the expos I've been to in the last few years have not featured members of the public handling snakes at all, and I think that many have a policy prohibiting this. Your post suggests that the risks are minimal and should not be of any concern. I would be careful about putting that advice on a public forum like this if I were you.
There are a few older keepers/breeders whom I know personally, who have seen the devastation that these viral infections can cause, and who now operate totally closed collections - a couple of them have had no new acquisitions for over 10 years. They breed their animals and are able to sell them for a premium price to keepers who KNOW ABOUT THE RISKS, and this is probably 5% of keepers.
Life is a risk, but we can, and mostly do, all we can to minimise those risks.
Jamie