list seems backward about pcf8574 HOT 2 CLOSED

The list isn't backwards, while yes, it may appear to be backwards, there's another possibility, the board you have may have it labelled incorrectly. I checked, and on a low-cost module I have bought from eBay with a PCF8574T, its the Pins that are labelled backwards.

from pcf8574.

As depicted in the code, Python lists are least-significant index first, so the following makes sense:

x = [True, False]
x[0] == True
x[1] == False

The list needs to be "backwards" compared to how we read binary, since you need to be able to do:

pin = 3
pin3_value = pcf.port[pin]

from pcf8574.