If a religion really were "true", would it need men's actions (Crusades, jihads, evangelism, etc) to defend it?

I can't answer for "God," but I can say this. If I were god, I wouldn't be the most elusive, misunderstood, vengeful creature that ever (never) existed. I wouldn't have several books that I allegedly "wrote" that conflicted themselves and each other and caused more killing than any other reason in history. And I wouldn't need anyone to beg or threaten others to follow me. So, to answer your question, no.