"If you define EA as "figuring out how to deploy a given set of resources so as to do the most good," your conclusions are going to depend on your value system: how do you define and measure good?"

I think more subtly it also depends on your calculation methodology. Rationalists talk a lot about the value of numbers for their Bayesian analyses and their "shut up and calculate" motto, but to my mind they overestimate the accuracy they have in their calculations by a lot. Of course I want to go with the 99% likely-to-help choice over the 25%-likely-to-help choice, but along with the fact my value system is indeed much different than theirs (in some important ways, infinitely so), I think all their Bayesian calculations need error bars in them. I think some rationalists would claim their probabilities have that error built into them, and I disagree. I think 75% likely is very different from 75% +/- 20% [1] when you start feeding that number through a chain of other calculations. A chain of calculations that nominally results in a 99.99% probability is a lot less impressive if a more honest calculation that propagates error bars correctly results in "somewhere between 2% and 99.9999%". It becomes more clear that the 99.99% is a very suspect number, even if it is nominally the middle of the distribution, especially given the number of times out in the real world the "highly improbable" ends up happening when it turns out that the assessment of the outcome being "highly improbable" was wrong. The probability distributions in the real world are highly pathological much more often than a naive analysis would suggest.

When analyzing the virtues of stealing billions to donate it to an effective charity, you better not just think that the value of the charity is higher than the cost of the loss of the money, you better be really sure your calculation is correct. I think the rationalists could argue amoungst themselves endlessly on the first point, but I do not believe they have any way whatsoever to establish their second point to my satisfaction, which renders the entire conversation moot, when there is no way they could ever convince me that their calculation is correct regardless of what it is. Even when my value system does in fact line up with theirs, and there is non-trivial overlap, I disagree with their calculation methodologies quite substantially as I think they consistently act with much more confidence then is justified.

Against that, I'm comfortable with the societally-evolved (evolution is important too, right, rationalists?) standard that in addition to the first-order effects of theft, one much consider the second-order effects of the dangers of normalizing outright theft because of the fact that someone else thinks they could use the resources better. Even if that is locally true, if everyone globally acts like that, global utility will plummet because everybody always thinks everybody else could spend their money better and the resulting chaos will not be helpful. (The Kantian imperative is completely inadequate as a theoretical foundation of philosophy but I do find it a useful practical tool, as long as one is aware to not place too much confidence in an extended analysis using it... the theme of this post comes up yet again.) The world is not improved by turning everyone into a central authority over all resource allocation in the world.

[1]: I know real error bars in probability space would never look like this, but mathematical accuracy would distract from my point here.