They don't simply collect all "documents" they need. They hoover up the data directly from various institutions. Your employer being one, your bank another, your medical aid, etc. Not only that, but they're getting involved with the IRS now via FATCA. It's actually awesome that they're probably doing a better job than the government itself when it comes to having an all-encompassing view of the tax-cattle that they oversee.
Oh, I am under no illusions that this was not a pursuit of excellence, but rather a way to make sure they get as much tax money as possible. Considering how 90% of all other government services are complete garbage.
But I still believe that paying taxes is the right thing to do (how else do you keep a country running, even a corrupt one?). And as someone who really hates doing any kind of admin, this was a breath of fresh air, and highly appreciated, even if their motives are not perfect.
