I always thought there should have been an enormous evolutionary pressure for humans to have different skin tones in different geographies. If sunlight is bad for skin than we should all be black or tanned all the time. However, if you don't live in a sunny area and you have a tan you might not getting enough Vitamin D. Vitamin D must be very important in order to make us evolve to have different skin tones and to tan according to the seasons.
The denominator should be the probability of the classifier being positive: P(True Positive)+P(False Positive)
Since you assumed that P(False Positive) = P(False Negative) = (1-P(True Positive))/2 = (1-P(True Negative))/2
In the algorithm case the denominator is 0.8x0.04+0.1x0.96=0.128
In the human case the denominator is 0.6x0.04+0.2x0.96=0.216
In summary, if a human thinks someone is homosexual, the probability increases to 11.1%. If the algorithm makes that call the probability increases to 25%.
The best way to memorise hundreds of different algorithms (or anything else for that matter) is to understand the few underlying principles beneath them. I would be surprised if he knew them all and couldn't come up with intelligent ways of mixing them for achieving a new task.
The human reaction time is about 0.1 seconds. They shouldn't use a manual chronometer to measure these results 4.9+/-0.1 is the difference between a world record and a good score.
They are giving poor people another choice they can have access to a very limited Internet or they can have access to none. If they would just loose lot's of money by giving people this choice it wouldn't be a reliable business and soon it would end. What's so bad about giving people another choice? No one is forcing them.. and it's way better than doing nothing.
It's easy to make python faster, you have PyPy, you can even program everything in python and then make a simple C code for the bottleneck and wrap it with python.
Php it's another example, Facebook uses php and it made changes to its compiler in order to make it way faster.
So bottom line, if people feel better writing in Python let's write Python and improve it to make it faster.