You said, "I have not heard of reasoning by Hindu or Taoists to avoid onions or garlic, I will try learn more about this."
The Bobo Ashanti don't eat them either. I'm not sure why the Taoist don't eat them. I know that in Hindu culture, they say that onions and garlic are rajistic and tamisic foods, in the mode of passion and ignorance. So yogis and those who want a more calm and meditative mind; they eat foods in the mode of goodness.
They say there are three modes(gunas) of material nature: Goodness (sattvam), Passion (rajah), and Ignorance (tamah). They say all things in the material world are operating in these modes.
What we eat and drink has an effect on our bodies, minds, and spirit.