I hate cigarettes, hate cigarette smoke, and wish no one smoked them...

[hunter]

100. As they used to say about Latex, Nickel, Formaldehyde, etc. etc.

The common definition of allergen is broader then the one you demand.

And even by strict definition, the sources you cite use weasel words like "not proven to be..."

Sure, it's difficult to find proteins in cigarette smoke, but one can still be allergic to it because of substances in the smoke that damage existing proteins in the body, turning them into true allergens. That's how the poison oak reaction works:

Toxins interacting with proteins

Another non-food protein reaction, urushiol-induced contact dermatitis, originates after contact with poison ivy, eastern poison oak, western poison oak, or poison sumac. Urushiol, which is not itself a protein, acts as a hapten and chemically reacts with, binds to, and changes the shape of integral membrane proteins on exposed skin cells. The immune system does not recognize the affected cells as normal parts of the body, causing a T-cell-mediated immune response. Of these poisonous plants, sumac is the most virulent. The resulting dermatological response to the reaction between urushiol and membrane proteins includes redness, swelling, papules, vesicles, blisters, and streaking.

Estimates vary on the percentage of the population that will have an immune system response. Approximately 25 percent of the population will have a strong allergic response to urushiol. In general, approximately 80 percent to 90 percent of adults will develop a rash if they are exposed to .0050 milligrams (7.7×10−5 gr) of purified urushiol, but some people are so sensitive that it takes only a molecular trace on the skin to initiate an allergic reaction.

http://en.wikipedia.org/wiki/Allergy

Without knowing the mechanisms exactly, it's still a very good bet that tobacco smoke is both an irritant and an allergen.

There is much "common knowledge" about tobacco smoke that simply isn't true and it's spread by the tobacco industry and by those who want to deny the damage they do by their second hand smoke.

Claiming "Smoke is not an allergen and doesn't contain any allergens" simply isn't true.