We are more likely to cheat towards forgiving ourselves than towards being harsh on others, hence the https://en.wikipedia.org/wiki/Nemo_iudex_in_causa_sua

While I do agree, I think a certain amount of caution should be maintained. When evaluating yourself, internal factors should still be considered as relevant data (albeit with no small degree of caution). If we make the Correspondence Bias about overvaluing external factors during self evaluation (as opposed to undervaluing them for others), attempting to correct for that does allow for the possibility of dismissing relevant internal factors which otherwise might improve the accuracy of our evaluations. This is no different than deciding that people who write bad articles are just having bad days, despite the fact that it should, at least in part, lend some weight to the idea that they are just poor writers.