(Ooh, I just know I should be listening to that l'il voice in the back of my head - rather than the multitude up front - that says, "Don't go in there" but...)
I believe you CAN get too deep into this issue. No one can be expected to delve into every aspect of a product and its manufacture before deciding whether or not to write copy for it ... any more than each of us, as consumers, can afford to do that before ever purchasing anything.
(This is not meant as a license to simply not care!)
As long you have no niggly-naggly feelings that you might be "taking advantage" of someone - and this is where your own personal sense of ethics and morality comes in - then go for it and do your best.
Keep in mind that you are "speaking" to people who (hopefully) are already looking for what you offer (or more to the point ... the benefit of what you offer). You're not dragging someone, kicking and screaming, off the sidewalk and pouring something down their throat with one hand while the other reaches into their pocket.
This is sales. And communication, of course.
And, as with selling refrigerators off the sales floor, you aim your pitch at someone (anyone!) who seems to be interested in what you've got. There may be many options available to them ... but, as long as you have "some" faith in what you've got to offer them, then you HAVE TO do your best to sell them on it.
Otherwise, you ain't in sales!
As for the chance that you are "taking advantage" of the people working in the (possible) sweatshop that manufactured it...
Well, with no offense meant to anyone, here ... if you don't sell that item and the plant closes down and all those laborers lose their only income (pitifully insignificant though it may seem to you or me) ... who really loses and benefits?
It's a tough question ... with no easy answers.
I'm a firm believer in going with your gut feelings ... and acknowledging that, sometimes, you won't get it right. If and when you find out that you were mistaken ... well, if you can, pull out at that point. If, on the other hand, it's too late and your copy is already "out there", accept that you're only human and you made a mistake.
"Intention" does count for something, in the great Karmic overview ... it's not only about results. (Of course ... "results" pay better.

)
Cheers -
Al