One of the most unpopular things about Christianity is its very exclusive nature. People in general are so full of pride that they don't like being told their most cherished beliefs are wrong. It is ok for them to claim they have truth, and it is theoretically possible for you to claim to have truth (as long as it's not something they don't like), but the moment you say Jesus is the way, the truth and the life, suddenly, that's arrogant.
While I have never seen The Princess Bride, I do so love the meme that springs from it: "You keep using that word. I don't think it means what you think it means." The standard definition of arrogance would be "an exaggerated sense of one's own importance or greatness". It is not arrogant to believe you have the truth, or that those who disagree with you are wrong. Indeed, if it was, we would all be arrogant. There is not a single unifying belief held by the entire human race. Is the Earth flat? I believe no, it is a globe orbiting a giant ball of burning gas in space. But some people out there believe it is flat. One guy even reportedly died because he tried to make a makeshift rocket in order to fly high enough to prove it. Am I arrogant to say flat earther's are wrong? Or those who believe there are 7 worlds, each layered on top of each other? Or those who believe the earth is held up by Atlas, or by 4 dwarves, or is floating on a turtle?
Or perhaps a belief is only arrogant when you're in the minority? Given that appeal to popular opinion is a recognised fallacy, I would say this doesn't work either. You can be in a correct minority. No one believed Copernicus and Galileo when they posited the Earth orbits the sun, but they still believed everyone else was wrong, and we now know they were right.
Final proof that it's not arrogant to believe people are wrong? If you say that, you're probably talking to someone you think is wrong. See, if they're right, it's not arrogant for them to think it, they are right to think it. So, the only way for you to say any negative thing about their belief is if you think they are wrong. But if you think they're wrong, it is better to show them they're wrong, not attack their character by erroneously and hypocritically claiming they are arrogant.
Of course, this is nothing new to humanity. The very attitude being addressed here today is the very attitude that nailed Jesus to the cross. Jesus preached that the religious authorities of His day were making a lot of errors, and they got quite cross with Him, so they murdered Him. Thankfully, this was the very thing that saves us all. By rejecting His truths and sinning against Him, we earn the wrath of God, but by faith in Jesus, we can be forgiven for this. Confessing Jesus as Lord and believing He rose from the dead results in salvation. The irony is, this is quite a nice truth. Yes, it's humbling, as we have to admit that we are sinners against the Holy God, but does it mean nothing to you that, although you deserve His wrath, He loves you anyway? So much so that He would take on flesh and die for you? That's the opposite of arrogance on His part, and the real height of arrogance is to believe you have the right to turn Him down.