I know they aren't just "trying to get high". The problem is that in order to get any psychotropic effects from Tramadol, the dose is so high that a lot of other really nasty effects will come with it. A 5mg dose of hydrocodone would accomplish the effect they are after with very little negative physical effects.
If they were just using it as an analgesic, which the article clearly indicated is not the case, it would be a different story.