The letter was signed by a lot of people, including many AI researchers, including people working on LLMs. Any dismissal that reduces to [one incumbent interest] opposes this" is missing the mark.
A lot of people, incumbents and non-incumbents, relevant experts and non-experts, are saying we need to figure out AI safety. Some have been saying it for years, other just recently, but if you want to dismiss their views, you're going to need to address their arguments, not just ad hominem dismissals.