Why so often when members fall away do they become so bitter and seek to destroy others’ faith in the church. It is as though they become a different person with completely different values. It breaks my heart.
To answer this as I think you intend, I would need to be able to read minds. So, instead I’ll look at it in a general view. (I can’t even read my own mind some days)
The reasons for disagreeing with religious doctrine are just as varied as the people trying to live faithful religious lives. This applies to any organized religion, let alone the LDS Church. However you are right in noting that those who do leave the church seem to over-correct, as it were, and seek the other extreme, whatever that may be in their mind.
I think the reason it seems like it happens so often is because they’re the situations we’re most likely to hear about. If someone just quietly slips into inactivity, then eventually joins another church without raising a scene or speaking out against the LDS Church, most of the time few people notice. Even at that, it’s rarely broadcast to the public. Let’s examine the Savior’s first parable in scripture, the parable of the sower;
3 Hearken; Behold, there went out a sower to sow:
4 And it came to pass, as he sowed, some fell by the way side, and the fowls of the air came and devoured it up.
5 And some fell on stony ground, where it had not much earth; and immediately it sprang up, because it had no depth of earth:
6 But when the sun was up, it was scorched; and because it had no root, it withered away.
7 And some fell among thorns, and the thorns grew up, and choked it, and it yielded no fruit.
8 And other fell on good ground, and did yield fruit that sprang up and increased; and brought forth, some thirty, and some sixty, and some an hundred.
9 And he said unto them, He that hath ears to hear, let him hear.
No matter where we might place ourselves or anyone else in this parable, we all have the potential to fall away from the glorious truths of the Gospel of Jesus Christ. As long as we strive to remain humble, and teachable, the challenges to our faith and our testimonies will be far easier to endure. The growth we experience after such trials can be amazing. Without due diligence to our testimonies, we’re just as likely to fall away as any other. What a tragedy it is.