Why are MCP23017 (port extender) input pins high by default?

Other Hardware General Electronics
7

In above link i can see piece of code as below which enables pullup.so by reducding external/physical resistor.

Will it work.

//--------ENABLE PULLUPS (default is off)-------------------
mcp.setGPIOABPullUp(0xFFFF); //all enabled
temp = mcp.getRegister( MCP23017_GPPUB );
Serial.print("GPPUB: ");
Serial.print(temp, BIN); //0 = pull up disabled, 1=pull up enabled
Serial.println();