I haven't thought about Alvin Earthworm in a long time, he was a flash animator that made a sprite-based flash Mario/Sonic crossover series called Mario Bros Z that was full of high action fights inspired by Dragon Ball Z, I'm not surprised that a kid would be into that.
As it relates to the poem, Wario and Waluigi play bit parts in the series, comically stumbling about in search of treasures as they find themselves in the middle of large scale fights and otherwise having no impact on the plot.
Clearly Sam was upset that Waluigi never took part in said battles.
