Why is (S)VGA 8BPP mode/8-bit color mode so debated as whether it shifts left or right?

Looking at the other available modes, they have one thing in common: they all shift left!
Then implementing the same in the attribute controller for 8BPP shifts and the sequencer for 8BPP fetching (perhaps using an 3-bit counter clocked(2 bits for going through the planes with the lowest bit for the nibble?) with the bits selecting the nibbles of the planes to read out (as a tap)?

All the attribute controller would need to do is simply shift the values left into it's latch and every second clock present it to the DAC? It also would make sense, because it's little-endian-like when continuing to shift for longer periods (presenting high,low(the high nibble being shifted high),high,low,high,low) using shifting?

Why is there even a debate why it would shift right? Wouldn't shifting right require extra logic for shifting (because it would need to set some bits and mask the old ones)?