That would be your contention that free will is not critical to salvation?
My understanding of Calvinism is that they don't even discount free will completely, but it would be better for people more familiar with it to expound on it.
I've never found the subject be resolved between the two theologies.
However, Both Calvinists and Arminians hold to salvation by grace through faith in Christ, not of works.
The only *wildly divergent* interpretations occur between Catholicism and Protestantism, not within Protestantism. Claiming that Protestantism is that divided is just an attempt to portray Non-Catholic churches to have more division within them than exists in order to portray the Catholic church in a better light, claiming that it's unified, therefore, better some how.
Joshua 24:14-15 14 "Now therefore fear the LORD and serve him in sincerity and in faithfulness. Put away the gods that your fathers served beyond the River and in Egypt, and serve the LORD. 15 And if it is evil in your eyes to serve the LORD, choose this day whom you will serve, whether the gods your fathers served in the region beyond the River, or the gods of the Amorites in whose land you dwell. But as for me and my house, we will serve the LORD."