I found it sometimes frustrating as well. But my experience was that it depended on the engineer/team/screener the Radar went to. Obviously if it was a bug I found, I much preferred to talk to the engineer in person who maintained the code in question.
There were plenty of teams that were very good about jumping on bug reports and getting right back to me. In fact, a decade or so ago at Apple this was more or less the rule.
My sense though is that engineering became overwhelmed with bugs especially as Apple itself became as successful as it has become.
"In the old days" a smaller team would have one of the engineers on the team screen Radars — maybe rotating to a new engineer every week or so. Engineers could quickly mark a bug as a duplicate of another (recognizing a familiar backtrace or symptoms) or might be able to guess at a diagnosis and send it straight to the engineer in charge of the (likely) relevant code.
A few teams I worked on were very good about daily "BRB"s (bug review board meetings). With a number of engineers in attendance, again, bugs were quickly dispatched to the right component, assigned to right engineer.
Again though, as Apple grew, I saw bug screeners on many teams more or less automatically flipping Radars back to the Originator if there was not a litany of documentation attached to the Radar. What build of the OS, what hardware, a full sample, system diagnosis.... It was frustrating when it was an obvious bug — maybe even a UI bug — that would take someone all of 30 seconds to repro. I somewhat sympathize though as traffic no doubt began to become a firehose of bug reports.
It seemed backwards to me though to put such a burden on the person who is simply trying to report the bug, trying to help you improve the software. Often in screening Radars the description alone was enough for me to know exactly where in the code the problem was. I didn't mind my time being spent at least scanning the Radar title and description. If it was not clear to me at that point, sure, flip it back for more info. The seeming rise of "auto-reject" is what began to irk me.