No, I'm not. the black veins are mold. Some edibly-soft avocadoes have much less black veins and black spots than others, but they all have some. Also by the time mold is visible, it is basically everywhere in the avocado.

But 5 out of 6 people can detoxify mold toxins, and those people can probably eat avocadoes without long-term problems.

None of that is correct. Ripe avocado's typically don't have any darks spots or "veins". Ones that are overripe or poorly stored can, but even then it's typically not mold, it oxidization. The "veins" are part of the structure, and thicker/woodier with late season, but not usually colored at all.

There is a fungal (again, not mold) infection that can happen from the stem end down, but that's rare and also not a harmful fungus for humans.

If there is actual mold on your avocado, you are storing them incorrectly or something.