To answer some anticipated objections:
As Luther aged, he recognized the threat Muslims were to Germany, and he spoke against them. But the princes who sided with him never fought against the Muslims, nor did he preach that they must.
Also, many people debate dismiss the quotes I provided, since they seem to lead one to antinomianism, and Luther opposed antinomianism. What Luther opposed, however, was the notion that sinning was as good as not sinning. He did find it preferable not to sin. At the same time, however, he denied both that the most horrific sins were inconsistent with being saved, and that committing certain sins could be lead to preventing other sins.
I think we find here in Luther a precursor to Freud’s sexual indulgences. Luther seems to be arguing that sin is harmful (although he seems to argue against any harm to the sinner), and that the experience of receiving forgiveness for sins helps remove the urge to commit that sin in the future. As if one might say: “Gee, I actually slept with so-and-so, and it’s no big deal, and I don’t feel the urge to do it anymore. I’ll be happy from now on with my wife.” Unfortunately, the truth is that experiencing sin scandalizes the soul, and can harden the heart. Or, they respond to diminishing enjoyment from the sin with an urge for ever more wicked sins.