On one hand, it is an example of the total-order mentality which impregnates society, and businesses in general: “there exists a single optimum”. That is wrong on so many levels, especially with regards to charities. ETA: the real world has optimals, not an optimum.
Then it easily becomes a slippery slope of “you are wrong if you are not optimizing”.
ETA: it is very harmful to oneself and to society to think that one is obliged to “do the best”. The ethical rule is “do good and not bad”, no more than that.
Finally, it is a receipt for whatever you want to call it: fascism, communism, totalitarianism… “There is an optimum way, hence if you are not doing it, you must be corrected”.
I'm not sure where you found this idea - I don't know any EAs claiming there is a single best optimum for the world. In fact, even with regards to charities, there are a lot of different areas prioritized by EA and choosing which one to prefer is a matter of individual preference.
The real world has optimums, and there's not a single best thing to do, but some charities are just obviously closer to being one of those optimums. Donating to an art museum is probably not one of the optimal things for the world, for example.
Then it easily becomes a slippery slope of “you are wrong if you are not optimizing”.
ETA: it is very harmful to oneself and to society to think that one is obliged to “do the best”. The ethical rule is “do good and not bad”, no more than that.
Finally, it is a receipt for whatever you want to call it: fascism, communism, totalitarianism… “There is an optimum way, hence if you are not doing it, you must be corrected”.