I think it means that whoever is saying this doesnt agree with what this man said, but he also belives that if what the other guy said shouldnt be said without defending it.
What the following quote "I may not agree with what you said, but defend to the death your right to say" may signify is that even though somebody might not agree with your opinions/ideologies, you must still stand your ground and not let anybody take your voice away.
The crusaders took over the holy land but they pope didnt want them their so he acted in war and disbelief of that anything bad would happen to his people no matter what would happen if he would loose or not
