Washed to reduce risk of residual bacterial contamination from the chicken (and handling/contact after laying). I don't think consumers of unwashed eggs wash them before hand since they're going to discard the shell and cook the egg, but in theory, they should wash their hands after cracking them and before touching any more food that isn't going to be cooked.
Also safer to eat raw if they were washed.
Taiwan study: https://www.sciencedirect.com/science/article/abs/pii/S09567...
US study: https://pubmed.ncbi.nlm.nih.gov/15553650/
But some older US studies from late 60s early 70s found no difference between the two (but maybe washing was different then):