I think it's undeniable that some of the behaviour of usually younger trans activists (and often allies) has been less than helpful and that misogyny, transphobia, and homophobia has played a part on all sides - the way Glinner treated women who disagreed with him on twitter was equally problematic. And these are powerful social forces which few movements if any are immune from.
But there is another dynamic within this which probably a lot of people weren't aware of. The original terfs, who were mostly US based although not exclusively, had been waging war on trans people for decades. Blogs like twansphobic were outing trans people and mocking them - ordinary trans people not activists - for years before this row broke out. In the 70s' lesbian feminist group The Gorgans turned up with guns in an attempt to intimidate a trans women and more than one person was physically attacked. In the UK, the lesbian sex wars as they became known sought to expel trans people from the growing LGB movement. People like Cathy Brennan and Janice Raymond played an active role in attempting to suppress trans healthcare in the US, with some success. The reason trans activists started wearing masks was because they were frequently outed by rad fem blogs (as they called themselves back then) and humiliated online. In this context the idea to host Julia Long as the main speaker at the Hyde Park event which really sparked this conflict on the left was a massive provocation, a bit like claiming you have reasonable concerns about immigration then booking Nick Griffen to be your main speaker. Long is one of the most notorous transphobic rad fems in the UK and has been equally hostile to sex workers - as have many others within her orbit. This very small tradition within radical feminism is openly trans eliminist, proud of it in fact, and has caused real harm to trans people over the years.
This is where the the initial resistance to terfs came from. The problem is a lot of people walked right into the middle of that, with what probably were genuinely reasonable concerns or questions, and had likely never even heard of Julia Long and Sheila Jeffreys and the rest, but became unwittingly associated with them. The nature of online debate only excerbated these tensions but what sparked it could probably be best described as a fuck up* - in that some people on the left became unknowingly associated with deeply transphobic individuals and others responded to that in a completely over the top way because they assumed that some curious random who went to a meeting was part of the same current as Long, Jeffreys, Brennan etc.
*although if you look back at the meetings being held by Sheila Jeffreys and others around 2013/14 I'd argue it was a loosely planned fuck up. And then the right wing press decided to join in, whilst the far and religious right also jumped on the bandwagon further inflaming tensions.
Just to add to this, I also think it has to be acknowledged that there is a huge power disparity at play in this conflict in terms of age, access to the media, and also class. Contrapoints, who has probably taken more shit from angry young queer kids than anyone, talks about how when you look at the timelines of those abusing her they are often literally begging for money for healthcare or housing because they've been kicked out of their home by their families. For all the characterisation of the trans movement as being comprised of Soros funded middle class students in reality many trans people, and especially young trans people are homeless, sex workers, unemployed, and have experienced a great deal of violence and discrimination due to being trans. They have no power in society, beyond being able to scream fuck you terf on twitter and so that is what they do.
The gender critical movement is largely a movement of lawyers, academics, politicians and celebrities who seemingly have open access to the right wing press to say what they want no matter how damaging to trans lives and in our society this is seen as all very normal, and polite and middle class - it's 'reasonable debate'. Trans kids don't have that power, and if a riot is the language of the unheard then that is what lies behind a lot of the most virulent shit on social media. That's not a defence of it at all, but it seems to me pretty unavoidable that a highly marginalised group of often very young people is not likely to respond to this debate in the same way as someone who can just ring up The Spectator and broadcast their views to hundreds of thousands of people without consequence.