What is now a long time ago, Google indexed the web properly. At that time it was an unparalleled feat of engineering. They solved scalability. They also managed to do this without sliding into "portal" territory and won their search dominance fair and square.

FB never did anything but being at the right place at the right time and were pretty nefarious from the very start. If any innovation can be claimed to have come out of FB, it's new ways of large scale psychological manipulation.

I suspect it's the memory of those early Google years that make some more lenient towards Google, although at this point, they really shouldn't be.