Confusing chronic Lyme for ME/CFS is different than saying they are one and the same. I think it is easy to confuse the two. Many individuals diagnosed with chronic Lyme may have ME/CFS, and visa versa. You can also have both simultaneously, as some of us on this forum can attest.
But acute Lyme that devolves into chronicity after treatment - or despite it - is chronic Lyme. The active agent behind the symptoms is Borrelia in chronic Lyme. Late Stage Lyme that does not respond to treatment is chronic Lyme. PTLDS is a different matter that may or may not be based on reality.
At least, that's how I see it.
But just like certain viruses, Lyme can lead to ME/CFS. When it triggers ME/CFS, the symptoms are not attributable to Borrelia.
Distinguishing the two becomes problematic in the face of dicey diagnostics. Swollen knees and PEM and NK function are a few things that address that.
I hope I am making sense here and not pissing anybody off. Bad brain day; hard to tell. This is all just my probably incoherent opinion.