That is true, at least until the Qantas F Lounge reopens (which is supposed to be this month), at which point Jl F passengers will have access to that lounge.

The access rules on JL’s site are:

”Star Alliance Lounge (First Class)" is available for only those who have a First Class Ticket and an accomapny as an alternative lounge. Both JMB Diamond and JGC Premier status members other than First Class Ticket are accessible to oneworld Los Angeles Lounge only.”