I kind of get why Argentina's clearly prefer Maradona, he has given them way more and represented something, I mean look what he did to England in the wc, especially abck then that must have been very sweet for Argentines. Messi is basically a foreigner from their pov no matter how he tries.
It was the same with Napels and Maradona, showed them Southern clubs could win scudetto's as well, giving poverty stricken people hope and happiness.
Besides all that I actually think he had more talent than Leo, just look at how extremely naturally talented he is, despite all the drugs/parties/weight gains.
Messi,Dinho and fenomeno Ronaldo are/were extremely gifted as well but Maradona is the only one that seems to have more natural talent.
Messi has a lot of things over him of course: longetivity, goalscoring machine, arguably better dribbler, professional, humble, best club footballer ever etc etc.
When you look at Maradona, what he has over Messi besides the international accomplishments: even better passing, tricks, better ball control, freekicks, leadership and he inspires more.
Its not that weird that they prefer Diego, especially if you add the nostalgia factor in.