Actually.. they do.
What needs to be known is that a commercial enterprise that sells an electrical anything to the general public is 100% wholey responsible for its safety. Even if imported, it is up to the importer/ seller to make sure it is compliant with C or CE tick and also it is tested and tagged as safe before it leaves the warehouse.
Fine for non compliance of certification ( C tick, CE etc) is $50,000 ( or it was a couple of years ago when i went through it). If electrical shock occurs or worse death then its a mandatory prison sentence plus fines.
Making a living out of selling electrical goods to the general public is not straight forward. Doesnt matter if it works or not... but it does matter that it is safe and labelled as such.
New in the box is different... its tested at factory.
Importing 2nd hand electrical and selling off "as is".. is nothing but a gamble that "she'll be right mate".... only takes 1 problem and its injury or worse death.
You need to be VERY careful with what you import