If that fact pattern holds, then unless there's a California law governing this that I'm not aware of --- and even then, federal supremacy moots it, right? --- I think they did straightforwardly violate the CFAA, contra the claim in their response.

I am extremely not a lawyer but the pattern of legal posturing I've observed is that some lawyer makes grand over-reaching statements, the opposing lawyer responds with their own grand over-reaching statements.

"My clients did not violate the CFAA" should logically be interpreted as "good fucking luck arguing that my good faith student security researcher clients violated the CFAA in court".