If letting go the $800k was purely PR, then that's some expensive PR. Who reads these blogs, a couple thousand people maybe?
They are investing $1B over all their funds.
Will the impact a founder-friendly reputation has on deal flow and close rate increase their fund's ROI by 0.8%? Almost certainly.
This is _brilliantly_ targeted PR. (To the extent that I suspect part of the deal with General Catalyst was that he blog about it and do his best to get it on the front page here...)