This site is being used to train AI, should we ban all crawlers, i.e. GoogleBot, Bing, Yandex, etc?

Isn't it better if the AI's learn from good sites like this one as well as, eg, Mumsnet.

Arguably yes, but there really isn't "learning" here, it doesn't "understand"... it makes a reasonable guess based on the probability of one word following another based on the statistics of what it's seen. The result is what appears to be viable and likely output confidently given, but there is no "expertise" because it hasn't actually learned, it's just mimicked.

What it mimics is based on what it was trained on, and means that your posting on websites which form part of the training set is the translation of your effort into free labour to train AI.

For me it's that part that rankles, not so much the quality arguments as with a big enough training set quality will be achieved anyway, but whether our interacting with other people, other humans, should form a source of free labour for machines and megacorps to profit from.

Thus it ever was is one perspective on that, but we can also take a tiny win and ban bots from this site to satisfy ourselves that at least the primary purpose of this site is for each other — a more human centric approach to the time we spend on here.