Although having a higher incidence of respiratory impairment is definitely contributory, I think it's probably much more simple than that. Smokers (regardless of type, including vaping) are far, far more likely to touch their mouths with unwashed hands while out in public. So I would presume that they are much more likely to be susceptible to surface contamination transmission. I'd say even
more likely with e-cig users... when was the last time you saw someone wiping down their vaporizer with alcohol?
I've often wondered how much illness statistics take that into account. Certainly tobacco use isn't
helping anyone's immune system, but I think the other behavioral aspects are at least similar in their impact - especially for those who work in public buildings. If you're in a densely populated urban setting and have to smoke outside... how many door handles and elevator buttons are you touching immediately prior to that smoke break?
As far as the direct statistics, it's also common for women to be much more proactive in seeking treatment earlier than their male counterparts... that could have a significant impact on the mortality statistics as well. Since previous coronavirus infection seems to have some factor, I'd guess that in general smokers have had more non-threatening virus incidents in their lifetimes as well for the above reasons.