I think the difference is that there is something to be gained in exchange for the risk posed by cosmic rays during air travel, so people are more interested in taking a nuanced approach to it. Meanwhile second hand smoke is a nuisance at best and a legitimate health concern at worse. Most people (myself included) are happy to ban smoking on airplanes or in restaurants even if the health benefits are negligible at best.

I do agree though, studies like this should always include useful context rather than just making absolutist statements. Perhaps alcohol and tobacco smoke need something similar to the banana equivalent dose used when talking about radiation exposure.