Tis just too complicated to crochet by machine - you're pulling a loop through a loop, one needle has to go through the piece, grab the working yarn, come back through the piece, go over top of the piece, grab the working yarn again and then pull that loop through the two loops already sat on the needle. Thats for the simplest stitch that 'builds' fabric.
You need fingers to manipulate that.
For clothing, you need to do far more complex stitches (I haven't learned them yet, I lose track!) involving yarn overs as well as the basic steps above, creating multiple chains before moving to the next stitch.
For the 'what can't machines do' nerds - they can't do double handed saddlers stitch either. Because the stitch requires two needles that pass through the same hole in opposite directions, switching sides of the piece each pass, creating a stitch that, if one loop is cut, still holds (whereas machine sewing the threads stay on the same side but are caught by the opposite sides thread, so if you cut one, the whole lot can be pulled free).
It is a valid point though - whilst some people are indeed being exploited by being paid what is to US a pittance, for work that is then being sold at a far higher price... what do those people live on if that work is taken away? They should be paid more, but how much are they being paid in comparison to other similarly skilled trades in their country? Is it still a pittance?