This is a hot button topic so what the heck, I'll weight in...
Well, I have to agree it is, and should be, considered more complicated than it may seem and thus requires lots of collecting as much info as possible and even trying lots of alternatives first. I think there is a tendency to focus on the kid but in reality there are significant contributions from the school side, the home front, other kids, diet, societal pressures, other health related issues, etc. For example, my wife is a HS English teacher. She typically gets the troublemakers/hard to teach kids that are more often than not already labelled as special ed (many on or recommended to be on meds for ADD and other conditions). She gets stuck with these kids for many reasons but mainly for two reasons, 1- she does quite well with them, often inspiring parents to do everything in their power to get their kid in her class, and 2- other teachers don't want them or won't take them.
This leads me to the more than just the kid point. She has literally seen teachers seek to force parents to put their kid on meds for no other reason than the teacher could not deal with the kid. Believe me, I recognize as well as anyone the difficulties teachers have dealing with hundred+ kids every day but don't think for a minute that there aren't situations in which it couldn't become school (system even) policy to shunt trouble kids into the "medicate them or we put them the school version of juvie" approach just so they don't have to deal with the kid (by making them more manageable) or so they can save on their expensive and difficult to find spec ed teacher assistants that would otherwise be legally required to place in the classes.
Of course, you also don't want to overlook the possibility of eyesight issues making a kid not pay attention or missing info, or potentially other health issues such as a dietary concern (such as hunger, limited nutrition which are all too common) and even recreational drug issues. There can be problems with other kids that translate to poor class behavior (oh man, my wife can tell you some stories on that one). And of course, although no one likes to admit this, home issues can bleed over to the kids class behavior as well. And finally, even if all the other factor/influences have been investigated/controlled and the appropriate diagnosis seems to fit, you still need to figure out if what is needed is simply more effort to help the kid gain self control using non-medicated means before going to the meds. This is especially important because there are degrees to every condition and just because a kid legitimately has ADD/ADHD does not mean it should automatically result in medication use. My cholesterol is high and I have to work pretty dang hard using diet and exercise to keep it reasonable. I could use meds but I would rather not unless I have to.
Consider also that there is mounting evidence that these meds aren't as benign as they were thought to be a couple years ago. No doubt there are legitimate uses and successes with the meds, but especially when it concerns the development of kids and potentially permanent changes/alterations (which one can only hope are for the better), it is worth considering every possibility and option before proceeding with long term medication in particular. The business folks call it due diligence, all the research and verification, before making an investment and I think the same thing applies here. Oh, and I have two kids, both have had this behavioral medication issue come up (only one specifically regarding ADD)- neither have or are taking behavioral meds and both are successfully managing/improving but it has taken a great deal of effort on our part (for one in particular). Personally, if our school took the approach you mention, we would likely pull our kids and maybe even move regardless of whether my kid, in the end, needed meds. This is because I think any school or system that takes that approach isn't one I am willing to have my kid attend.
I could go on but I shouldn't so that's my 2 cents worth of babel...