You're absolutely right. I'm querying a novel to literary agents right now, and it's the same way. The official channels provide absolutely no feedback. That's exactly what's frustrating about it.

You need to look for feedback elsewhere. There's a risk of getting bad feedback if the person isn't actually involved with making decisions, but it's better than just talking to friends (or not talking to anyone at all). And if you're willing to iterate and experiment, you can figure out (at least indirectly) how good the feedback is by the results you achieve when you put it into practice.

I personally provide mentoring to junior members of my community (as a researcher in HPC) through conferences I attend. In my writing life, I look for feedback at writers conferences. I'm not sure what the equivalents would be in other parts of the job market, but something similar might help.

Feedback's tough. I sometimes sit on content committees for conferences. Sometimes for a given abstract my feedback would be along the lines of "Did you even try?" or "How many different events did you submit this generic abstract to?" But mostly it would be more along the lines of it's OK but there's a known person who is better plugged into this particular topic who also submitted and their abstract is sharper.

Conferences do often try to get new and more diverse speakers but you're still competing with people who do this sort of thing for a living. The bottom line is that a lot of feedback would be along the lines of "You were fine but someone else really grabbed us in one or more ways."

Feedback like "Did you even try" is just as useless as "You were fine but someone else was better." Why not simply state what's wrong with the abstract, and how it could be improved?