You can not compare the acceptance rate of StockStack Overflow with the acceptance rate of Meta.
That said, it depends also on how many questions you asked. In your case, you asked 383 questions. So 51% acceptance rate means around 190 questions which have no accepted answer.
My first impression is that this is a high number of unaccepted answers, yes. Heck, it's even a high number of questions without even looking at how many have accepted answers.
Obviously, to be certain, one would have to check if there are a lot of maybe subjective/cw questions. Maybe questions without answers?
But we all know people go with their "first impressions", no?