I'm assuming you mean IE.
>nobody should be surprised when Bing plays dirty and intentionally degrades the experience for Firefox users in an attempt to compel a switch to IE
MS would never degrade performance on their own platform. Tying IE into Windows was different; they made the default work better than the alternative. They're not going to intentionally make Bing shitty for FF users; they'll just go elsewhere. They might integrate Bing and IE more fully, adding features and making it more difficult to use other engines, but they would never intentionally degrade their own product.
I dunno what make you think Google is "less evil" than Microsoft in that area. It's just business. Deal profits Google, Google makes deal. When the balance changes, Google will stop making the deal.
While I don't believe that selling the default search spot is problematic, I do believe it's risky and dangerous to make that the primary source of revenue, especially when the major potential bidders have serious conflicts of interest with supporting Mozilla (that is, they provide competing or incompatible services and products).