Reading between the lines
If you've ever been rejected (grad school, an article submission, a job) you may have spent some time analyzing the rejection letter itself, reading between the lines, trying to figure out why you were actually rejected.
The thing is, there's almost nothing written between lines.
People rarely say what they mean when they reject you. It's just not worth the risk. Not worth saying, "I'm filled with fear about taking this sort of chance on you." Not worth the blowback of saying, "you're a miserable writer, the bane of my existence, and you will never amount to anything." It'll just come back to haunt them.
And of course, if you do read that sort of apparently honest screed in a rejection letter, it's just as likely to be about the writer as it is about you and your work.
Make a pile of the thousands of rejection letters that successful people have received over the years and analyze them for insights and patterns—you won't find much of use.
Short version: You got rejected. The words and the tone of the rejection aren't going to tell you much, and every moment you spend dissecting them is a way to hide from the real work of making something that will resonate tomorrow.
If you really want to know why someone didn't like your work, you're going to have to put a lot more effort into it understanding the person who rejected you. Reading the tea leaves in the rejection letters and one-star reviews is pretty worthless.