I find even true hard core believers will hide things, they sort of rationalize the behavior in their mind, it doesn't mean they are having doubts. People are blind when it comes to their own issues,while still being judgemental when it comes to others.
The society even gives tacit approval for it if you are an elder. They have said if the past misdeeds was a while back and the elder is still serving faithfully it's a sign that Jehovah has forgiven him. We have all heard of elders that had long term affairs, cheated in business for years, etc. When caught they usually take the punishment and get reinstated. And they were in on judicial committees the whole time, passing judgement while engaging in worse behaviours of the own. They are just hypocrites.