Lamar Smith has no business being on that committee, much less acting as its chairman. He either has no understanding of the material, or ignores his understanding for political reasons.
NOAA had been complying with Smith's demands for some time, but Smith continued to make greater and more unreasonable demands (one might guess he did this in order to find *something* he could use to castigate them with). Eventually, NOAA finally put their foot down, and stopped complying. This led to Smith's letter, in which he threatened Kathryn Sullivan, the administrator of the National Oceanic and Atmospheric Administration, with civil or criminal enforcement of his requests. He went further, threatening to subpoena Commerce Secretary Penny Pritzker, under whom NOAA sits.
Now, this all might seem okay, if Smith had a stated goal, or reason to suspect malfeasance. But he's not given any. He claims to have "whistleblowers" on the inside, but he doesn't reveal who they are, or even what they have told him.