Because:
a) it is not possible to tear it down and start over with good material/intentions/ethics
b) they do not want to change their model, because they are making money from their current practices
c) it is a VERY useful tool for evey government's dark/shady practices (gag order + give-us-everything)(exactly what every dictatorship does)
d) people need to be protected even if they don't understand the risks (e.g. houses are built following a code - even if people don't understand that walls need X material and I-beams need to have Y width).