Do people really call it "mercury" or "organic mercury"? It's on par with pounds as a measure of mass, weight, and force by the amount of confusion, I'd say

No, I doubt it. There aren't very many uses for dimethylmercury due to its potential lethality. I would assume the people who actually use it in a lab setting are going to call it dimethylmercury, especially considering organic mercury usually refers to methylmercury, or one of the other less harmful organomercury compounds.

I think the confusion probably stems from the original article about the scientist who passed. Dimethylmercury is made from a reaction of methylmercury, and they are both organomercuric compounds.