Maybe I'm just feeding the trolls here, but why? He wasn't hiding it. I can see a disclaimer needed for something that's open to bias like "competitor X sucks and beyond is way better", but just for saying he likes what we've done?

He had nothing to do with this fundraise, he's had nothing to do with the product so far. He saw the link on HN, said he thinks it's great. I hired him because he thinks it's great.