Because if you can make it more difficult for the EPA to use scientific studies — require repetition of experiments (or exclude studies you can't repeat) and disclose all raw data (even if it's based on medical records or trade secrets), then you can delay scientific conclusions.
If you delay scientific conclusions, you delay having to act on them via regulation.
If you delay regulations, people can make more money.
But, hey, with a snazzy nickname like the "HONEST Act," how could we go wrong?
Republicans’ War on Science Just Got Frighteningly Real
Two terrible bills that Obama would have vetoed are back in play, and they stand a very good chance of becoming law under Trump.