Just my opinion.
(1). Jealousy - Nissan Skyline is one of the world's most popular car along with Suburu WRX Sti, Mitsubishi Lancer Evolution that is still in the car market today unlike Toyota Supra, Toyota MR2, etc.
As some of them are getting old, only some of the owners who are the real Skyline enthusiasts keep the car in great condition unlike some wankers who buy, thrash and sell them back because they can't maintain it. So when non-Skyline car enthusiasts see the bad examples on the road, they take it as all of them are in the same state and think their car is better than Skyline.
(2). Easy to find, buy and drive - Therefore, more wankers on the road that ruin the real Skyline enthusiasts reputation.