There's no guarantee that they were cross-contaminated, only that there's a possibility. I'd personally eat them, no problem, as I'm not allergic to peanuts. Usually equipment is cleaned very well after processing, but there's still a small risk of the previously-processed food to get into something else.
The issue with the legumes is the lectins, and there are lectins in TONS of foods. It's about HOW MANY are in the legumes. Cross contamination would be a very very minor issue because you're already eating lectins in other plant foods.
As it so happens your digestive system if otherwise not being abused has a fair amount of ability to deal with lectins. Does that mean you should eat red kidney beans? No probably not.
But you may have noticed there's actually a lot of paleo/primal people whop eat peas and green beans, because the lectins are lower. Also proper cooking will deactivate many lectins.