Because this is a transparent attempt to rein in the EPA on the grounds of 'science'. Seems OK as a sound bite, doesn't quite work well in the ugly real world. As noted in TFA, there are two major, practical objections:
- The EPA doesn't get enough funding to do all of the studies by themselves. And there seems to be no mechanism in the proposed legislation to fix that little oversight. So it becomes an issue of perfect rather than practical. Sure, it would be best if everything were publicly funded and every bit of data published on the Internet, but it is arguably better if some 'imperfect' data is used rather than the very limited amount of data that is openly published.
- Longitudinal data, by definition, isn't 'repeatable'. You don't get to rewind the tape (if you are unfamiliar with this analogy, look up 'VCR' and similar ancient technology).
The way this bill is crafted makes it perfectly clear that good science is not the goal. Emasculating the EPA is.