Viking haven't "suddenly popped selling seats directly to the public via the internet..." They have always sold seats directly to the public as do many other charter airlines. Not suprisingly the seats on the flights cost more if booked directly - if you charter a whole 737-800 you will get it at a cheaper price per seat than if 180 people buy the seats seperately. As a charter company you then have to charge your customers enough to cover that cost along with all your other overheads, which Kiss and Goldtrails appear not to have done.
They are not ATOL protected - this is nothing to do with them being Swedish.
If you buy a ticket from Ryan air it is not ATOL protected, and they are Irish. But there again, if you buy a seat from Easyjet, Jet 2, Bmi Baby, Flybe, Eastern, Air South West, Virgin or British Airways, to name but a few it is not ATOL protected, the ATOL scheme only applies to package holidays.
Sadly as a result of the collapse of Goldtrails and Kiss a lot of those who have worked for Viking are now losing their jobs. However Viking are still in existance, still employing pilots and cabin crew, just scaling back their operations. It is noticeable that companies like Thompson and BMI can announce redundancies and fleet reductions and we don't see pprune covered with threads titled "BMI bust", possibly because a few posters on pprune don't have a personal axe to grind against Sir Michael Bishop, for example...