Kimbo grapples at a white belt level. About 18 months of grappling experience with Bas Ruten as head trainer, starting at 32 yoa. That is why people think they have a chance against him. Yea, he's strong. But he isn't quick, doesn't have good hips, doesn't have good balance, doesn't have good cardio, and doesn't have any experience. Experienced and competitive blue belts and purple belts - even if they are 70 pounds lighter - SHOULD be able to hold their own and even get the better of someone like Kimbo Slice. You act like his 'professional' status somehow makes him a better grappler. It doesn't. Many of us train with plenty of serious athletes and/or professional fighters (many of whom are more experienced and more skilled than Kimbo, just lacking the marketing machine behind them), and so many of us know exactly how and what we can do against larger guys who fight for a living but who have obvious holes in their grappling.
I can't speak for anyone else, but I know that my 15 years of competitive grappling experience gives a lot of the bigger fighters at my gym plenty of trouble. I out-wrestle them, then when they're on their backs, I out-grapple, out-quick, and outwork them. Would I beat Kimbo? I don't know - never grappled with him or anyone who has. But I know what my gameplan would be, and from my experience against similar guys, I believe I would have a good shot at beating him. And you can email that to him. It's nothing personal, I'm just far more experienced on the mats than he is, and believe I would come out on top.