"men who had been colleagues suddenly found that they had to choose between friends and the Church which had nurtured them. ...those who had converted felt the need to persuade others to join them. Because they knew intimately the Church..., converts were able to attack its weak points. As a result, many... felt beleaguered. This was further exacerbated by the attitude of the authorities of the Church..., which appeared... to be saying sternly to unsettled men that they should go, whilst simultaneously the [other] Church... seemed to be beckoning and welcoming."*
It's an imperfect analogy, but it rings true for me.
*Credit where credit is due: this is from Michael Chandler's book An Introduction to the Oxford Movement.