To be fair, you have to have a very high IQ to understand Waluigi. The humor is extremely subtle, and without a solid grasp of self pity most of the jokes will go over a typical viewer's head. There's also Waluigi’s mischievous outlook, which is deftly woven into his characterisation - his personal philosophy draws heavily from internet memes, for instance. The fans understand this stuff; they have the intellectual capacity to truly appreciate the depths of these masterpieces of culture, to realize that they're not just funny- they say something deep about LIFE. As a consequence people who dislike Waluigi truly ARE idiots- of course they wouldn't appreciate, for instance, the humour in Waluigi’s existencial catchphrase "WAAAAAA!!!" which itself is a cryptic reference to the portmanteau of Luigi's name and the Japanese adjective warui.