You're giving Bing waaay too much credit. Right now, I have 11 guests, 5 search spiders, and one user. Normal for this small forum with very little activity at night.
Of the 11 guests, 5 are bingbot. And 3 of them are walking this silly thread that has 99 pages. Long continuing threads confound the search spiders. Every time there is a new post, they spend a long time walking through every page in the sequence of pages.