Agents and editors are not our writing coaches. They’re not there to teach us how to fix mistakes we should have learned in craft classes and writing groups.
If our manuscript is close, if it’s getting there but still needs work, that’s our issue, not theirs. Hence the form rejection. Any kind of personalized rejection means they see something of value in the work and they want to encourage us to keep on writing. Congratulate your self on each of those efforts, because some agent or editor thought you were good enough to deserve the extra time in their already overfull schedule for that little encouragement. The form rejection takes a few seconds. That note meant they spent long minutes composing a note specific to you and your effort. Read it, treasure it, print it out and frame it. And then get back to writing more things. Because, unless they specifically ask to see a revised version, they don’t want you to send that piece back to them. So don’t antagonize someone who likes your work by by handing them the same piece they already rejected after a few unasked for revisions.