For hundreds of years, Viking real estate agents had a field day thanks to the name, I suspect. Every minute a new sucker is born, among Viking's too.
Also, the Vikings wanting to get the hell out of Greenland would continue to have an incentive to lie to the ones who had never been there: like to be able to sell them their assets that are fixed or that they don't intend to take.
Had Erik called it "Frozen Wasteland", that would have been it. No hundreds of years of settlement, nothing. The few lunatics would continue to have a hard time convincing anyone else to join them.
On a similar vein, Iceland was also named from a first impression, having been initially reached at a colder time of year.
Thos are the explanations that I have heard. There is no way to know if they hold any truth.