My partner is Spanish so I know a little about this partly as her father (now passed away) was always supportive of the other side and still pretty much a republication/communist (idealist himself in the Marx philosophy) till the day he passed away about 8 years ago. While Franco was a dictator and there's never been a good dictator, he wasn't as bad as many and quite possibly one of the better ones at least towards the end given he put in place a system to return Spain to monarchy
and a democratic one at that and that's not an easy thing to pull off but it worked and in some ways the Spanish should thank him for that as otherwise they might not be free enough to judge him now.
In an alternative outcome of the Civil War, I have doubts Spain would be a democracy today if the communists had won so in that sense Franco was the better of two evils that were the only two options.
Re the actual relocation of his body, I don't agree with that it and in general think its just plain wrong to dig up & relocate anyone long buried just because some fractional number of people in Spain (<30% iirc) have a view against him being buried there when the fact the place
was commissioned by Franco and his intended resting place so perhaps its the other bodies that should be relocated but I wouldn't want that either.
History is history and we shouldn't make attempts to erase it however distasteful we may find it and the people associated with it, it was a different time. Or perhaps those that agree with the relocation think we should also dig up lots of Kings and Queens who no doubt at least up to the 18/19th century were personally responsible for having people put to death. Lets throw in Cortez and other 'explorers' too and remove their statues, in fact lets pretend the world used to be a far nicer place 50, 100, 1000 & 2000 years ago than it is today and erase all bad people (need definition of bad...>1 killed?) so people who have issues with history and the past can sleep easy at night.
https://en.wikipedia.org/wiki/Valle_de_los_Caídos