Paul Graham is a really smart guy who has helped a lot of great startups, but that doesn't mean he's always right. He responded to a really incendiary post attacking a company he's trying to help succeed with a response that wasn't as carefully considered as it might have been.

If the original post had been of the form "It's a shame they're working with Monsanto because", then I expect he would either not have replied, or would have made a more measured response, but with a similar substance: when you have a startup that you're serious about growing, you sell to whoever you have to in order to keep the business moving forward. I'm not sure whether I entirely agree with that sentiment, but it's not that surprising for a pragmatic, fairly apolitical libertarian.

There are only two things that are disappointing at all: that he seemed like he was trying to slam the door on the debate, and that he disagrees with you. The former happened because he made a cranky response, while the latter can only be disappointing if you naturally expect someone as smart and likable as pg to agree with you on things like that.

I would say that this warrants taking a deep breath and relaxing first, then responding calmly and carefully.