If you're a working politician, you have some idea of what actual legislation and policy looks like. And it doesn't look like it was written by a fifth grader with crayon while watching My Little Pony. And that's more than you can say of anything involving the Green New Deal.
(Even its name is silly.)
So you can't help but feel a little sorry for Rep. Durbin. But not very sorry. Guys like Durbin were fine with radicalizing their party. They just thought it would stop somewhere reasonable and it no longer does.
Durbin is able to say the obvious because he has zero realistic presidential aspirations. Meanwhile nearly every 2020 Dem or Dem with any presidential aspirations is obligated to sing its praises.