Because there's a fundamental difference between "manufactures a car with well-understood features in a mature regulatory space" and "prematurely deploys untested and unprecedented functionality without oversight." If a legacy manufacturer rushed out a product that ignored regulation, for example, they should be similarly subject to prosecution.
There are no requirements in FMVSS that meaningfully apply to FSD, unless you want to consider AEB part of FSD (which it isn't). Tesla voluntarily follows ISO 26262 for the parts they consider safety critical (i.e. not FSD), but that's just a generic software process standard. ISO 21448 is both uncommon in industry and voluntary. Tesla does not follow SAE J3016 terminology internally. Tesla does not follow UL4600. Tesla flouts both the CA DMV and the NHTSA reporting requirements. Etc.
Can you point out where there's meaningful oversight that Tesla cooperates with without complaining or missing data?
There's lots of oversight in the automotive space; everything from the dashboard indicators to the crash standards are tightly regulated. Perhaps the regulators should be 'better', but it seems to me that Tesla is quite compliant (as it does 'recalls' and all the like). Which regulations is Tesla maliciously failing to comply with?