> Uncustomized spambots are also so unintelligent that they do not correctly answer simple questions such as “What is 2+3?”, or “what color is this website?”.

I found that some uncustomized spambots are able to solve simple math challenges like this one.

And the color question is bad for accessibility.

Many of the suggested alternatives are also terrible for accessibility, because they require solving a visual puzzle, without an audio alternative.