Real still has high-powered board members openly active in the Falange, including the descendants of Franco, his generals and Primo de Rivera running their respective neo Nazi organizations and actively encouraging neo Nazi hooligans. That's why the decent folks in Madrid support Atletico. I know the area and the football culture there. My late father was the Bangladesh ambassador to France, Spain and Morocco and I spent a LOT of time there.
Catalans and the Basque don't just "drag in" the Franco connection. What happened is unresolved and therefore unforgivable. Much like the Pakistani-Razakar issue here.
"And do not curse those who call on other than GOD, lest they blaspheme and curse GOD, out of ignorance. We have adorned the works of every group in their eyes. Ultimately, they return to their Lord, then He informs them of everything they had done." (Qur'an 6:108)