Islamic literalness CAN and DOES lead to literalists being cruel to dissenters and non Muslims.
Billy, I think I would argue that yes 'Islamic' literalness can and does lead to literalists being cruel to dissenters and non-Muslims if we are talking about ineterpretations of hadith, tafsir etc. But I don't think the same argument can be made for literal interpretations of the Quran itself. Indeed we know from the following verses:
‘’God forbids you not, with regard to those who fight you not for (your) Faith nor drive you out of your homes, from dealing kindly and justly with them: for God loveth those who are just.
God only forbids you, with regard to those who fight you for (your) Faith, and drive you out of your homes, and support (others) in driving you out, from turning to them (for friendship and protection). It is such as turn to them (in these circumstances), that do wrong.’’
60:8-9
''Unto you your religion, and unto me my religion.''
109:6
''Let there be no compulsion in religion: Truth stands out clear from Error: whoever rejects evil and believes in Allah hath grasped the most trustworthy hand-hold, that never breaks. And Allah heareth and knoweth all things.''
2:256
I think the verses really speak for themselves.
And of course there is not anything like 'death to apostates' anywhere in the Quran itself.