Im am literally the last person in the world to defend anybody from the FIA... but, the DRS activation point/zone is a fair bit of guess work this year and so far i think they have done a pretty good job, with one or two exceptions of course.
Having to take into account different track layouts, car speeds, fanboys etc. cant be easy to calculate. The expectaion from fans for the FIA to get it perfectly right every race in the year of its inception is just not reasonable
Next year, if they continue to fcuk it up, then everybody can let rip