I listened with interest to two Roman Catholic friends of mine speaking to each other about taking their doctrines seriously and they both agreed that they didn’t believe in a literal approach but were happy to remain churchgoers.
In JW land however, the cultural norm is to take everything rather more seriously. The slightest hint of disbelief is treated with horror! It would be symptomatic of disloyalty to the GB that you are becoming an unbeliever and that would mean being destined to become bird food at big A. It is the worst thing ever to express religious doubt in JW company. Doubt after all is far more contagious than belief!
Therefore, they have no valid reasons to remain (other than for fear of losing family and friends). In a normal church you have the freedom to believe (or not believe) whatever doctrines you want.
Also, please note that all the nonsense you see them explaining and defending should be place in the right perspective. They are not defending any teaching and doctrine. They are defending their choice of remaining JWs and they do that for fear of losing what the WT gives them to feel the comfort they need.
That's the thing. They are not really JWs if they reject JW doctrine. Many of them reject the GB as well. So... why not go to any regular church?
I think what they are trying to do is to redefine what being a JW means. The problem with that is that there can be no clear definition unless they all agree on what doctrines constitute JW doctrines. They might as well start a new denomination with a new name.