I notice that it's not just bing, why on this very site I see that 18 of your 22 submissions (all within the past 13 months, all to your blog) are marked as '[dead]'.
Random guess: maybe because people see that all submissions are self promotion and they flag it?
'[flagged]' appears to be a strict subset of '[dead]'. Trawling thru the 'New' tab it looks like '[dead]' by itself appears to be a soft ban on the site ('soft' because any individual link is salvageable by votes)
But submissions here doesn't have anything to do with Bing indexation.