Companies are not people, concepts like “consideration” or manners don’t apply. Either someone, or several people, in the company dropped the ball, or they found a candidate they liked and terminated the process with other candidates. Expecting personal consideration from an organization is just going to lead to disappointment.
Maintaining a coding test repo and documentation is probably pretty low priority, and the people administering the test (HR) probably don’t put the test together or maintain it. They could interpret messages about broken links in any number of ways, maybe not even understanding the problem, maybe not knowing who is responsible, maybe getting ignored by the programmers who might be able to fix the links. They might have candidates in the pipleline and then get told by the hiring manager that someone was hired already, or that the job won’t be filled right now.
I would apply a variation of Hanlon’s Razor: don’t attribute to malice what you can explain with organizational dysfunction. Communications problems, mixed signals, and unclear responsibilities are typical of organizations, not an exception. The problem you describe could have happened for any number of reasons that have nothing to do with consideration. We can imagine how they might have a better process, but then think how you might react if you worked there as a programmer and someone from HR emailed you about broken links in a coding exercise you haven’t seen, when you have “real work” to do.
Since broken links and bad documentation are fairly common in programming projects I might have pushed ahead and done my best with what I had rather than throw up my hands and wait, or complain about the poor documentation. Maybe that wasn’t possible in this case. I get incomplete and vague specs from my customers all the time, and they expect me to fill in the blanks and do the best I can anyway.
I’ve had this kind of thing happen in my career many times. I don’t take it personally. If the organization isn’t driving the hiring process and moving it along with me I assume they are either going through the motions (already have a candidate with an inside track) for legal reasons, or there’s enough internal friction to stall the process. A lot of companies have set up ridiculously complicated interview/hiring processes. I wouldn’t waste time on an IQ test or a coding exercise unless I was sure I had made the short list already. I would have tried to bypass the HR process altogether with contacts or going straight to the hiring manager (recruiters can be good at that if they have connections).