What do you think is behind it?
Well, I suspect we both hold a scarcity of facts. However, standing out here on the sidewalk, it is my sense that most if not all of the folks with the slightest involvement in Cohen's conviction, or that could have influence in the penalty phase or even thereafter in the incarceration phase - are anti-Trump. Cohen's public statements to both voters and the House, perhaps represents their final shot at Trump in this particular affair.
Of course, Cohen's carefully narrowed and tailored testimony to the House was designed to enthrall a number of people who would love to find yet additional charges that would support initiating impeachment proceedings.
IMO, the House is not necessarily looking for a solid case, they just want to flood the MSM with all manner of assertions through the primaries and perhaps beyond.
You, of course, could be correct, that Cohen was/is a willing, even eager participant. On the other hand, I think Cohen is smarter than that but nonetheless ultimately submitted to pressure.
Hope you have a nice evening.