presumably because they more readily transfer across membranes and various barriers in the body? That's an interesting point, is something organically derived more easily integrated into biological tissues than something of synthetic origin? I'm not sure that logic is sound but it's an intriguing thought.
You can dip your hand into a bucket of pure elemental mercury, and you're generally fine (though I wouldn't recommend it if you have open cuts or wounds).
On the other hand, dimethylmercury (an organic compound with mercury in it) will readily absorb through your skin (and latex gloves!) and is so potently toxic that a few drops of the stuff will kill you.
None of this is tob say that synthetic, non-orhanic compounds are in any way certain to be safer. However, organic compounds certainly do have advantages in integrating in the body.
> That's an interesting point, is something organically derived more easily integrated into biological tissues than something of synthetic origin?
I don't get what you mean with organically derived. Organic chemistry covers a lot of synthetic chemicals. There is no reason to assume that organic pesticides are more readily absorbed by the body. There is also no agreed upon definition of organic pesticides, they are not limited to pesticides synthesized from plants. It also includes several minerals.