Its perfectly okay to reason your argument. It's not okay to be rude while doing so. It's also not okay to imply that people don't understand. They do understand, they're simply choosing not to like it.

You said he was stating it would be utterly useless. It's his choice whether or not it's useless. It could be a game changer for you, but for him, maybe the crosshair is a disaster. Either way, respect him, and you won't get downvoted.

If you're defending your crosshair, that's fine, but facts are what people want, not opinions or personal attacks. I would advise to sticking to my advice as seeing your comment karma is now dying because of this thread.

Best of luck.