I'm not sure if doing chores in and of itself can be viewed as on a continuum with being tortured, for the purposes of this exercise. Being forced to do chores is considered bad for two reasons (as far as I know): Most people find doing chores to be intrinsically not enjoyable, and most people have other goals that they'd prefer to spend their time pursuing. Being tortured matches at least the first part of that description, and usually matches the second part as well. But for house elves, doing chores is not intrinsically not enjoyable, and it appears that they generally don't have other significant goals to pursue - and this is their native state; if you create a house elf from nothing, rather than modifying another creature to be house-elf-like, there's no 'rewiring' involved at all. (And the OP made a point of specifying that that's the case, since it is obviously problematic to rewire a creature in a way that's opposed to its values.)
It may be useful to also consider the case of masochistic people, for whom things like being whipped are enjoyable: Given that some people seem to just naturally be that way - it's not caused by trauma or anything, in most cases, unless I've really missed something in my research - is it somehow problematic that they exist?
My lower brain agrees with you. My upper brain asks if this is just a trolley problem that puts a high moral value on non-intervention.
Scenario A: Option 1: Create house elves out of nothingness, wire them to enjoy doing chores. Option 2: Create house elves out of nothingness, wire them to enjoy human desires.
Scenario B: Option 1: Take existing house elves with human desires, wire them to enjoy doing chores. Option 2: Leave existing house elves with human desires alone
Is there a non-trolley explanation for why it is immoral to rewire a normal elf, but not...
Edit: This is old material. It may be out of date.
I'm talking about the fictional race of House Elves from the Harry Potter universe first written about by J. K. Rowling and then uplifted in a grand act of fan-fiction by Elizer Yudkowsky. Unless severely mistreated they enjoy servitude to their masters (or more accurately the current residents of the homes they are binded to), this is also enforced by magical means since they must follow the letter if not the spirit of their master's direct order.
Overall treating House Elves the way they would like to be treated appears more or less sensible and don't feel like debating this if people don't disagree. Changing agents without their consent or knowledge seems obviously wrong, so turning someone into a servant creatures seem intuitively wrong. I can also understand that many people would mind their descendants being modified in such a fashion, perhaps their dis-utility is enough to offset the utility of their modified descendants. However how true is this of distant descendants that only share passing resemblance? I think a helpful reminder of scale might be our own self domestication.
Assuming one created elf like creatures ex nihilo, not as slightly modified versions of a existing species why would one not want to bring a mind into existence that would value its own existence and benefits you, as long as the act of creation or their existence in itself does not represents huge enough dis-utility? This seems somewhat related to the argument Robin Hanson once made that any creatures that can pay for their own existance and would value their own existance should be created.
I didn't mention this in the many HP fan fiction threads because I want a more general debate on the treatment and creation of such a class of agents.
Edit: Clearly if the species or class contains exceptions there should be ways for them to pursue their differing values.