It really isn't appreciated in the U.S., I can say that much for sure.
Probably mostly due to low-ratings during its air on the late-night Adult Swim. If Detective Conan's earliest episodes (which were dubbed in English to a point) where directed at a younger audience, maybe a 3:00am time slot was a bad marketing idea. That proposed "younger audience" would most likely be asleep or not allowed to watch it (Adult Swim)!
Detective Conan isn't so suggestive or obscene that it needs to be on the adult programing. People can be caught in questionable situations (rarely) and are murdered, but the same can be said for other anime series that they do still play (or have played) on Cartoon Network and other channels! (Bleach, Dragon Ball Z, Yu Yu Hakusho, Cowboy Beebop, Vash The Stampede...)
Though, I have also been made aware that in the U.S., since we have had situations of young children bringing (most likely fake, but often real) guns to school, we want to avoid showing that influencing material. For example, there are a lot of people pointing guns at other people in Detective Conan, which is likely one of the main reasons it was put on Adult Swim and away from its direct audience's eyes (aside form the murders).
Oh, to live in such a world.