"For all have sinned and fall short of the Glory of God." - Romans 3:23
The misconception here is almost understandable. Faith in Jesus is the reason we have salvation. Therefore, so some conclude, it is the lack of faith in Jesus that is the reason for damnation. It seems pretty simple when we look at it that way.
Unfortunately, it is incorrect.
Nobody is damned for not believing in Jesus. We have all committed crimes against God. Every single one of us has sinned. In fact, we all sin more than a few times every single day. If anyone is condemned to hell, it is not caused by not believing in Jesus, it is caused by sin.
The reason people go to hell is because their sin separates them from God. On the other hand, if they put their faith (i.e. trust) in Jesus Christ, we accept His offer of forgiveness. So, we are condemned for legitimate crimes against God, but we are offered pardon by accepting or rejecting Jesus as Lord and Savior. If we accept the offer, we are pardoned and found innocent. If we reject His offer, we are subject to His justice and are found guilty.
If we want to see an example of why lack of faith in Jesus does not actually condemn us to hell, one need look no further than their medicine cabinet. Most people have a small bottle of Tylenol (or some form of acetaminophen) in their medicine cabinet. One common use for this medicine is to reduce fever. If we were to apply the same logic from above to the Tylenol, we would have to say that since Tylenol reduces fever, the lack of Tylenol causes fever. Do you see how silly that sounds?
So, let's be sure to think things through carefully and when people raise objections that are superficial and shallow, we are there to gently, humbly and graciously correct their thinking when it is flawed like this.