We should simply not continue this conversation because we fundamentally disagree. I don't get out of bed for "I don't care".
This other developer has put this new business at risk of closing. Maybe you don't care, but someone somewhere does.
I've only seen that once in my career. One developer rewriting existing code constantly, to such an extreme degree it's unfathomable.
He rewrote large amount of scripts (often overnight). Other developers would wake up the next day or continue the project next week, only to find a swath of issue reported by users and the project is gone (rewritten and moved). Did that for while, destroying the work of many people across a number of teams, making enemies and leaving a trail of projects ablaze. Didn't manage to get him fired (organizations rarely fire people) so over time other developers simply stopped working (what's the point when it will be undone the next day) or left.
At first, I thought this was the normal junior mistake. Reading code is quite hard, so one reflex of junior developers is rewrite existing code to make it "prettier" or "better", of course it's just a path to understanding the code because they understand what they just rewrote after the fact. One aspect of learning real world software developer is to stop the urge of constantly rewriting like that.
But that was not it for this developer, he went on and on never learning. Trying to mentor lead nowhere, his stubbornness and deeply ingrained vision was stronger than the will of any lead or manager. Worst challenges were, he fundamentally disagreed on almost all objectives, required features and design decisions, he simply had a different vision and ideals deep down that there is nothing you can do to reason about. He was ultimately unmentorable and unmanageable.
this reminds me of Steve Yegge. He did a post on the difference between employed developers and entrepreneurs, and how they're completely different creatures.
You've allowed yourself to become a pet and you've given up the ability to care about your work for food and you think it's a moral failing in others who have not.
You're to be pitied.
I don’t think that you „fundamentally disagree“, but that you have different understandings on when the time has come to quit caring. And given the limited amount of things we can care about during our lifetime I find it certainly helpful to reevaluate from time to time what I decide to care about.
I agree that your coworkers behavior is harmful to a team’s productivity and I would seek the conversation to resolve the disagreement in a professional manner. But if there is no path of a resolution, I would escalate the problem, stop caring and get on with my life, because there is nothing more I could’ve done.
meanwhile, the rest of humanity understands why we're ok with being labelled intolerant due to "intolerance of intolerance is itself intolerance".