Because he won that war and ruled country for a long period of time.
Ton be fair, that was a better deal then what people in US prisons get. It is not a hideous relic - it is just history. Franco actually did keep Spain out of WW2. Ironically, if commies won the civil war there, Germany would have steamrolled them in 1940 and obviously would make short work out of British to the South, "locking" the Western Mediterranean, giving Axis powers heavier strategic advantage.I'm sure the guys in US prison working a few cents an hour would take that deal if they were not in prison?
On balance I think Spain is stuck with the hideous relic. But Franco should go the current state owes him no particular honer amidst the dead soldiers. When Spain buries Juan Negrín next to Fraco I'll call fair. Fraco was despot he at minimum and should be removed. He did not keep Spain out of WW2, only Hitler's unwillingness to sort out all the conflicting demands of Spain, Italy and Vichy did and his hard for a two front war. Franco was hot to join that's a man who does to be there. Or maybe he dose alone with that grotesque monument after everyone else is interned someplace else.
But than again I think is was a grave mistake to allow a confederate memorial at Arlington.
You just seem to express same kind of sentiment that is generally used for barbaric destruction of historical sites. Its a good thing that people who share such opinions are a fringe minority.