People like consistency. I think this helps explains Corbynmania amongst his supporters in the Labour party, and also to an extent Brexit.
I think that because Corbyn refuses to compromise, he engenders support amongst people who dislike compromise. This could also apply to those who want "Hard Brexit" or mean to bounce Theresa May into it.
This is my theory, so much as it is. It's not meant to apply to everyone, but is after trying to think through how I'd end up supporting Corbyn or Hard Brexit, that I thought if I was someone who believed in no compromise, I might have come to that POV.
In pretty much everyone's daily life, they have to compromise. Perhaps a person is slightly overweight and needs to have a salad rather than a burger for lunch? Perhaps a person can't afford to go see Bruce Springsteen because they have to pay the mortgage? Perhaps they'd love to go to Turkey for the family summer holiday but their spouse vetoes it due to fear of terror attacks?
Plus of course, there are all of the roads not taken - the job they didn't take, the course not pursued, the person not asked out on a date. All of these may inform a self-image of "I didn't do that = I can't do that = someone's preventing me from doing that"
Perhaps they don't like this and feel anxious about (as they see it) not getting any autonomy - and autonomy is a key human need.
Back to politics, I think flexibility (most of the time) is an important skill in politics- as you have three main interested parties in what you do : yourself (which includes family needs), your party and the country. Balancing the needs of the three is a continuing challenge and part of the skill is getting it right.
Jeremy Corbyn doesn't even seem to try the last two. I think this makes him a bad politician.
So, in the face of the daily, grinding compromise, people and causes arise that arise that people can project onto. People like Corbyn who don't seek to find a consensus, appeal to those who think that's all you need to get what you want, be that equality for all or exit from the European Union.
Being inflexible tho, is not a good thing. Getting to a "win/win" situation is much the best outcome if possible. Of course there are some cases, such as the UK being under mortal threat, where you don't really want someone to be seeking a compromise, but mostly, it pays to see the other side and "get you both to yes". It's harder than banging on about what YOU want, of course.
It was suggested to me that Corbyn has compromised on having a free vote over Trident and also on campaigning to Remain in the EU. I think tho, that neither were compromises that he believed in - on Trident he is continuing as if he has changed Labour party policy without taking his party with him, and the free vote was more of a cop-out than a compromise, and on Remaining in the EU, I think the problems with his attitude have been covered elsewhere, but his support was lukewarm at best and totally scuppered by his call for immediate hard Brexit after the vote.
So, perhaps no compromise is a sensible attitude if you want to attract fervent, single-minded support, but is it really a good way forward?