Whatever his motivation is/was, one of the most insidious aspects of the TRA ideology is how difficult it is to reverse ferret.
As soon as you "join" you are overwhelmed with positive and affirming support. You're equally instructed to cut off any negativity.
So down the rabbit hole you go.
I read a really upsetting blog from a girl who'd de-transitioned. She'd become completely dependent on her online support and their validation of her transition, having been urged to block anyone who didn't offer their 100% support of her trans journey.
Then, she started getting some "uncomfortable" (you can guess...) communications and when she expressed her discomfort she got accused of kink shaming and threatened with a mass block of all the "friends" she had come to depend on.
It's a well known tactic.
You'd think JM would be too clever to fall for this (and there is no doubt he is very clever but he's also I suspect very ambitious and fame hungry).
Like others, for a time I suspect he enjoyed the adoration of the TRA's and each tweet that got him more "likes" (the more on board he got) played to his SJW mentality and the desire to be celebrated.
That's his Achilles heel.
He's too clever to be wrong so however the ridiculous the argument he wants to play in response to the Bell case, he's going to do it anyway - because being told by his peers he's lost the plot is far better than admitting to himself that he's fucked up and failed to understand the issues at hand.