Not to be pedantic, but having studied this topic previously, I would like to jump in here and make a few corrections of what you have just stated.
Strictly speaking, a concentration camp is a place where large numbers of prisoners detained for similar reasons are housed in a high density (hence the name). All the others are merely additional characteristics which may or may not be seen in concentration camps. Japanese Americans were interned in concentration camps too, but it had none of the characteristics you mentioned. Interestingly, the same went for the Francoist concentration camps too.
Firstly, the prisoners were not detained simply because of ‘political beliefs’. These concentration camps were set up in the midst of a civil war. All civil wars will have prisoners of war, and those prisoners need to be held somewhere. The same went for the American Revolutionary War, and the again during the Civil War. I also highly doubt the Americans let captured Japanese or Germans roam freely. (As a side note, the Jews were not held because of their political beliefs, mind you. They were held simply for being Jews. It does not fit your definition of a concentration camp, but everybody agrees that that is part of the true horror of the Nazi concentration camps.)
Also, the prisoners were not ‘worked to death’, neither were there mass killings of prisoners after detention (however, one must remember that they did execute many Republicans they thought beforehand could not be ‘rehabilitated’). Those that died in prison did not die of the hard labour itself, but rather of poor hygiene and poor nutrition. This was less due to being deliberately deprived of food, but it was part of the general shortage across the country due to the over-exportation of agricultural products, which was one of the many failed economic policies of that regime. Naturally, the detainees ranked lower on the list of priorities than the other citizens.
To top it all off, the Spanish fascists also closed the concentration camps by themselves after the war. They also protected the Jews from the Nazis. This by no means rationalises their actions, but those certainly mitigates them from your comparison with the Nazis. There is so much more to the differences than just language.
Anyway, I have no wish to use this to defend the killings and human rights abuses that went on during the regime. The point I want to drive across is just this: Stop comparing Franco with Hitler. It’s a tired topic, and it does little justice to all the work historians do into researching the events of the Franco regime, just to have people blithely toss it all aside and get away with a vague idea that it was exactly the same as the Nazis. Also, don’t make assumptions about all other circumstances simply because it was called a concentration camp. Not all concentration camps are the same. The Japanese Americans who still continue to work in the US despite before detained and distrusted by the very same country can testify to the faith they still have in America.