The short answer is that alcohol has been part of the accepted culture since the dawn of writing, whereas tobacco was a relatively recent import from the 'New World' for non-indigenous people. There is also the relatively recent lesson in the failure of alcohol prohibition which is deeply ingrained in Western culture.

None of this should be taken as an argument in favor of drinking, I just wanted to offer some context for contemporary attitudes, which aren't shaped by accurate risk assessment; few human policies and attitudes are shaped by accurate risk assessment.