Hi, I ran into the same issue and from a search looks like several others have as well. The site that dropped for me does not have any links built and is in Google News and Adsense approved and no duplicate content and has regular posts.
I opened a ticket and they escalated to engineering but not expecting a resolution. Seems to have started for most back in Oct '21, mine was removed in Dec '21.
Only change I made was adding Adsense to the site about a week before the removal. I have seen a few others mention they moved to cloudflair right before the drop but really no consistent pattern.
The only clue I have found is looking in Site Explorer and filter for urls with malware. Almost everyone I talked to will have the majority of their site show up here. I believe Bing might "roll up" a malware detection to affect a whole section of a site, or even the whole site.
I checked my site and sure enough, I have a bunch of URLs that fall into this filter and figure this is the reason for the removal. The real question from my end is what Bing crawler is seeing as malware. I have scanned the site and it is clean. Only thing I can figure is something with the Adsense implementation based on the timing of adding Adsense and the drop from the index.
Will post back if I hear back from engineering or figure it out.
