Clean modern buildings, desks, air conditioning, running water, very nice. You were fooled by that photo into making a bigger assumption about the full school and situation.
OP may have misunderstood the context but I think it's a stretch to say they were intentionally fooled.
One thing I can tell you that the whole situation up there is contentious and complicated between the tribes, the states and the feds where one could support any argument as there isn't some standard "Rez Life" one can point at.
I mean, I used to have this one friend who grew up (and still had family) on a part of the reservation which was completely surrounded by the other tribe and her and my other friends (from the other tribe, don't quite remember which was which here) would get into some serious arguments at the bar over the issue where we'd have to separate them before it came to fisticuffs.
The real world isn't TV. Not everything is a grand conspiracy.