OpenAI is doing cool stuff, and this tenet sounds nice. But what right do they have to advocate for policy on behalf of all AI researchers and developers? They could easily shut off branches that are not conducive to commercial applications requiring their research, even by accident. They might miss moral edge cases that could ultimately benefit humanity while trying to close off potential risks. They could encourage institution of a policy that limits US effectiveness against China's AI. I could go on.
The more competition there is in AI, the lower the potential for any one rogue agent - whether it be a corporation or autonomous machine - to dominate and take the whole field in wrong or dangerous directions. Eventually there will be a whole AI subfield dedicated to combating regressive effects of other AI. Legislation at this stage might prevent key developments.
Edit: Perhaps I should more charitably read this as a push against the corporate lockdown of AI.