I suspect the real reason for the unease, from some, of the FDR data release is simply because it breaks with tradition. But think it through. Traditionally, FDR data has been kept confidential until an accident report is issued, sometime years.
Not true, it's sometimes released at the time of a public hearing.
We’d be naive to think that investigators, even with the best will in the word, didn’t use this confidentiality to allow delays – and to, unwittingly, colour their conclusions to suit their personalities.
A fantasy to support why it should not be confidential?
Investigating teams release the information after the various personalities feel that they agree that the data points are valid. There are no lingering personality traits left in the agreed data points.
Far better to get the data out into the open, earliest. After all, it simply reveals what the aircraft was doing at the time. Why it was doing it is another question - for the formal investigation to answer. There’s enough aviation nous on this web, and others, to gain useful and early information from the TAM FDR which may just prevent the analysis of another FDR.
The problem with this is that only the investigating experts (in the lab) know how the points are detected and fed to the recorder and within what precise time frame. There is also some interpolation necessary to confirm correlation with all the other various recorded data. Then of course comes the analysis against the expected performance characteristics of the aircraft about its various axis, let alone the system analysis that is looking at the on-off bits of various inputs like brakes, spoilers, squwat switches etc.