Gatti got in purely because of his popularity, nothing more (well, maybe his premature death helped too). If we start talking about accomplishments, we could count about a 100 fighters that deserved it ahead of Gatti (and Vargas for that matter), but what can you do. Vargas ain't getting in simply because he was a solid champ but never proved himself truly elite, and he was ruined too early in his career by Tito to have put together a great reign or resume. Also, while popular in his day, he wasn't on Gatti's level, so he ain't getting bye in that way.
I loved watching vargas and if it was up to me he would be hof bound. never know tho, he is/was better than many fighters currently in the hof