Tell that to the tomato plant. Toxicity of the leaves depends on when and where they are cut from.
Not too mention the chemical reaction that happens within a tobacco leaf after the plant has either been allowed to flower or has been topped. Bearing in mind bright leaf can also be harvested by priming leaves as they mature instead of stalking the whole plant at once. Leaves that are categorised as ‘red’ would be picked last, after all of the different headings have been removed. The extra time on the plant, as well as being the only leaves left would influence their chemical make up.
As mentioned above, “red Virginia as a product” has been processed (ageing, pressure, blending, case - moisture, casing etc), and then also impacted by consumer storage and smoking style, all culminating in the properties of the smoke as it is drawn into the mouth.
I am highly sensitive to smoking red Virginia as whole leaf, straight or blended. I can however manage the reaction by cadence and tongue placement, and a heavy dose of high alkaline leaf in a blend. In fact I sometimes enjoy the slight bite/tang that it can bring to a blend when used condimentally.
The room note and pouch note of “red Virginia products”, thinking along lines of sutliff krumble kake or their stoved red ribbon, makes me want to puke.
Much of this thread appears to be about semantics. I’m happy if someone uses the term allergy to describe an intense, instant and unmanageable discomfort caused by a higher ratio of red va in a blend.