I never said Fairphone was more unethical than its competitors, only that it claims to be more ethical and its main marketability is on the basis of this claim. If you didn't care about ethics in phone production, would you still buy a Fairphone over any other phone? I don't think so. Aside from their claims about ethics, the only thing that sets them apart is the modularity, which I do think is a positive and possibly that's enough for some people, but I'm personally more concerned about the ethics of phones. If Fairphone is not substantially more ethical than its competitors then a lot of their customers would buy other phones, because other phones may have features that Fairphones don't have.
And for the record I don't think any ethical phone exists nor do I think it's possible to ethically make a modern smartphone. There's no ethical way to mine cobalt, and if you dispute that I challenge you to go work in a cobalt mine. Phone production is evidentially terrible for the environment and many of the natural resources required to make phones cannot be extracted without incredibly unpleasant and frequently deadly labour, which nobody would voluntarily do. I think it's good enough that Fairphone is supposedly making an effort to mitigate this, and if you need a smartphone I don't think there's anything wrong with buying a Fairphone. But I think it's quite obvious that the reasons to buy one are undermined significantly if Fairphone is engaging in much of the worst of industry standards.
It seems like an incredibly disingenuous representation of criticism of a tech company to say that it's "all or nothing" to be swayed away from a company that specifically markets itself as an ethical alternative (which Google, Apple, Samsung, Huawei, etc do not market themselves as) when they could be getting something they may consider to be a better product from another company with similar working conditions etc.