On the issue of the disconnect between Halacha and morality, and hermeneutics.

Does this mean that there is no ethical consideration behind a certain law (moral, say the Rabbis' prohibition on marrying two wives)?
More generally, do you attribute to laws only internal halakhic considerations (interpretation of ancient sources) or also extra-halakhic considerations such as ethical or judicial considerations?
When Rabbi Shimon said that something that is not intended is permitted, does this mean that this is how he interpreted the verses, or does it express a certain philosophical view of his (say, a person's actions are meaningful only if they are done consciously in a way that they are done for them)? In other words, is a poske's interpretation of ancient sources distorted by his philosophical and ideological views?