Many volcanic soils are not good to farm in. Costa Rica for one. Some of the most aluminum toxic soils on the planet.
And does this aluminum toxicity go away after liming to an appropriate pH? The volcanoes and acid soils of Costa Rica have not much in common with azomite, an alkaline aluminosilicate marine sediment of partial, 30 million year old volcanic origin. Costa Rica does not indicate that soils free of volcanic influence or azomite are anywhere near free of aluminum. Nor does it mean that volcanic soils elsewhere are poor: https://volcanology.geol.ucsb.edu/soil.htm
Costa Rica does not mean that aluminum toxicity to plants in soil acid enough to make aluminum soluble has anything to do with azomite or its use - in fact, applications of up to 600 lbs/acre has been shown to increase rather than decrease yields. This is according to their site, but even if the people are getting free azomite in return, it doesn't mean that they are falsifying the results.
The fact that some plants which grow in particularly acid soil absorb aluminum in some part of the plant does not mean other plants growing elsewhere in something other than sand, water, air, or coir have leaves, fruits, or flowers full of aluminum. It also does not mean that the result of growing something in soil with a pH of 4-5 can be liberally compared to soils of higher pH.