The wife of Migros founder Duttweiler was absolutely against alcohol and tocacco, at a time when many workers spent the money they got at the end of the month (cash) for booze right away. In the old days you got your wage cash, in my case from the wife of the company-owner
Therefore, Migros does not sell alcoholic beverages or any form of tobacco
Duttweiler started his business by bulk-buying staples like flour, sugar, etc. and bagging it into much smaller, affordable bags, then selling it from a mobile shop (van). In much the same way as the early english Co-op stores used to break down large quantities of goods and food-stuffs, then pass on the saving to their customers.
As Wollishofener says, the absence of beer, spirits and tobacco was to try and prevent the men blowing their wages on booze and fags.
Port Sunlight and Bourneville in England were founded with similar principles, the factory owners controlling the local shops to avoid drink problems amongst their workers.
So why does the Kioski inside the Migros sell smokes then? And who needs Migros or Coop when Denner has a lovely Chilean Sauv Blanc for 4 CHF?
Seriously, though, I think Migros may be clinging to a rather tenuous ideal when the booze sold by a subsidiary is next door and the smokes are inside the store. It's a bit like saying you don't support prostitution, but have a kiosk on the grounds selling women. Sure, it's not you selling it directly but....everyone knows the connection.
If the Kiosk is Migros, it will not sell alcohol, but if it is Kiosk AG, it is different. Denner is 100% Migros owned. Also Globus is Migros owned, and has a nice assortment of wines.
Consider Migros being a meeting point in downtown city areas, also for youngsters. Where you will not find Denner, Aldi and who knows who else sells alcohol at cheap prices.
And it's far more difficult for teens to get alcohol and tobacco from kiosks and high price alcohol stores than from a simple supermarket.
And regarding the MMMs in the suburbs you can assume that youngsters will more easily have lunch or a coke there rather than on the parking place of a nearby Denner.
For shops and kiosks alike, they only can sell beers and wines to those above 16years of age and spirits only to those above 18 . Rather bad is that there now are laws making sales of alcoholic stuff impossible after 2200. The childish idea is that such a move will keep young people from buying booze. While they now simply go shopping BEFORE 22.00, and possibly buy more than they would otherwise