is asking companies not to accept local discriminatory practices when
doing business abroad a sign of disrespect for local cultures or is it
a sign of our commitment to human rights?

It all depends on whose side you're on. 

To take a non-discriminatory issue and make it into one that you might
see how pompous it is to assume that we americans are so superior:

If you don't like the fact that 9 year olds in india are making your
clothes, is it really fair to tell the mother of that 9 year old she's
abusing her kid who's bringing home the only food they can afford?

Likewise, is it really fair to tell someone who has a god given belief
that women should be treated like property that his god was wrong?

How you do business is strictly up to you, but I think the real
message you should take home is that, before you decide to tell people
how you want them to do their business that you should spend the time
and look hard at the cultural issues you don't like.  Discuss it and
understand the people and the culture, then you can decide.

Just let them know up front that you do business only with companies
that adhere to certain policies.  Let them know that it would be a
waste of both parties' time to have any discussions if this basic
point cannot be agreed upon.