Since you asked "why wouldn't he?", here's why:
I spent quite some time trying to work around the glitches, which I was helpless to do anything about. So then I spent some more time writing up a detailed problem report including screen snapshots of Chrome debugger traces showing where some of the problems were. When I didn't hear back from them, I put even more time into trying to work around the glitches, and found even more, different glitches. So then I spent even more time writing up those problems in detail and sending them in. Then I continued to wait for a reply. And waited. And waited. And so far I have never received any acknowledgement of any of my problem reports. And none of the problems have been fixed. I have much better things to do with my time than to help AngelList debug their web site, and wait for a response before finishing my profile. Now my profile is still in a half-finished inconsistent state, because I went on to more important tasks, and have never heard back from them since then.
The first problem I reported was related to inappropriate unsolicited email that Angel List sent to my former employer on my behalf without my consent, applying for a job at a company I used to work for, presumably with forged headers and first-person pronouns making it seem like it came directly from me:
I added an entry for a company I worked for, XXX, and when looking at that page, I was surprised to see a button that said “[checkbox] Sent” in their Jobs section. I did not mean apply for a job there, and I do not remember doing anything that expressed my intention to apply there — I used to work there, but I’m working somewhere else now. There does not seem to be any way to list all of the jobs that I have applied for (or that AngelList applied for on my behalf without telling me), or DELETE any applications that I may have mistakenly made. Can you please remove my application for a job at the company I used to work at, XXX, or explain to me how I can do that myself.
How am I supposed to fix the problem myself, without access to their source code and servers and databases? Don't you think the ball is in their court to reply to my bug reports, after I've spent so much time unsuccessfully trying to work around it myself and writing up and sending in bug reports?
Or are you suggesting I start my own web site from scratch to compete with AngelList, instead of spending my time reporting problems that I have with AngelList to their team who ignores me, or even spending my time on my real job that I'm trying to describe on AngelList?
Was I wrong to spend so much time trying to work around the problem and writing up bug reports, when I should have instead spent my time watching a Ruby on Rails in 10 Minutes screencast, developing my own competing web site, deploying all the infrastructure required to publish it, hiring people to maintain it, getting the money together to run it, and renting office space? Should I use AngelList to get funding for that, in spite of all its flaws? Or are you offering to fund my AngelList competitor yourself?