Many people reject biblical truth because when they hear it preached, it wasn't what they've always believed.
Many Christians have put themselves into different 'theological camps', and as a result, they become afraid to leave their doctrinal comfort zone. Even if their doctrine is wrong.
People keep tradition or break tradition, based on their experience with the people surrounding that tradition. For example: some people will stay with false doctrine, because the people who taught it to them are 'nice' and have good Christian character. Sadly, other people leave good doctrine, because the people who taught it to them did something 'bad' and have poor Christian character.
The ideal is to find good Bible doctrine, taught by those with good Christian character. The best 'camp' to be in is the "what saith the scriptures" camp. This 'camp' strives to teach right doctrine and live godly lives. They recognize the importance of both.
If you almost drowned as a young child because you couldn't swim, it's no reason to teach your child to be afraid of water. That may be the comfortable route, but it's better to educate him or her on the dangers of water and teach him how to swim.
The same with biblical truth. It's better to warn others about the dangers of 'man', but also teach him how to rightly divide the word of truth.