Reason being that previous periods of American legislative politics were characterized by back room deals unknown to the public. This afforded politicans an opportunity to strike bargains with the opposition without having a spotlight trained on them (and being crucified in the next primary for "working with the enemy").
The check was that every 2/4 years voters still had an opportunity to toss out the incumbent based on his or her track record of results. (Admittedly without knowing how the sausage was made)
While I agree that transparency is a good thing, I'm humble enough to admit that the US legislative / election process is complex and has a lot of feedback. So the article's thesis seems plausible.
Which do you want more: non-partisan cooperation or absolute-transparency?