All elements being replaced in my list instead of 1 during each iteration

Question

I am creating a program which will simulate a smart lights system in a home. My code is below with commments which explains what each part does.

import os 

# this code retrieves all room names from the text file "rooms.txt"
# if the file is empty, the code will direct the user to another menu to enter room names
def loadSettings():
  roomNames = []
  file_path = 'rooms.txt'
  file = open("rooms.txt", "r")
  # checks if the file is empty 
  if os.path.getsize(file_path) == 0:
    print("This appears to be the first time you have used this device, directing you to configuration menu\n")
    settings()
  else:
    reading = True
    # reads all the room names from the text file and puts them in a list
    while reading == True:
      currentLine = file.readline()
      if currentLine == "":
        reading = False
      else: 
        roomNames.append(currentLine)
    print(roomNames)

  # when the room names are retrieved from the file, this section of code puts those names into another list, along side with a default status (the lights in that room being 'off')
  # the new list should look like this: [['room1', 'off',], ['room2', 'off']]
  rooms = [["placeholder"] * 2] * len(roomNames)
  for count in range(0, len(roomNames)):
    print(roomNames[count])
    rooms[count][0] = roomNames[count]
    rooms[count][1] = "off"
    print(rooms)
  # goes back to main menu when the list "rooms" is set-up
  mainMenu(rooms)

However, during the execution of the code, the part where the 2D array called 'rooms' is setup, I get an unexpected output.

[['room2\n', 'off],['room2\n', 'off']]

I'm aware of how to remove those '\n's but the final list doesn't have unique rooms. It should look like:

[['room1\n', 'off],['room2\n', 'off']]