Yes, and killing one person for being religious is also one too many. Also, how do you know how many people the Spanish Inquisition killed specifically for heresy. There were people on trial in secular courts for other crimes, who would say something blasphemous in the court room so the Spanish Inquisition would try them instead - they blasphemed to get a fairer trial.
Communist dictators and the people who worked under them, they had henchmen, soldiers and employees - some of whom would've shared their views. Look up "The League of Militant Atheists." That was thing in Soviet Russia. It's a fact that the atrocities people like you love to hold over the heads of us religious people are also found just as much - if not moreso - among the non-religious. You give us too little credit, or give yourselves too much. Not every atheist is a communist, but practically every communist is atheist, and even then some didn't stoop to these violent levels. From this and previous statements of yours, you come across as the "tar all Christians with the same brush" type person. I hope I'm wrong, but if I'm right, it would be hypocritical for you to get bothered when you think I'm tarring all atheists with the same brush - though I'm not.
Stalin was atheist, Pol Pot was atheist (he made religious affiliation in Cambodia a capital offence), as was Mao Zedong. Remember when I did my "No True Atheists/Scotsman" post with Richard Dawkins?