Salamun Alaikum.
I’ll share a crude analogy if I may which forms part of my personal opinion.
If 'Riba' is forbidden (no matter how one defines it), would it be correct for us to sell purely ‘Riba’ based packages to others? Would it be correct to work in an office that only dealt with ‘Riba’ based packages?
If the God of the Universe is forbidding something, why would we engage in any associated activities for others?
Now in a licensed convenience store where one may work, ‘alcohol’ is not the main item of the business. It has other lawful items, such as food (frozen, canned and boxed), fish, fresh vegetables, fruit, lawful drinks, groceries etc. Therefore, the intention is not to only sell ‘alcohol’ but to provide other ‘good’ things too as a service to the customers. It just happens that alcohol is also sold as part of the proprietor’s choice over which you have no control. This would be no different from working in any other large supermarket chain.
Now working in a bar or an exclusive ‘off-licence’ would be a completely different situation where alcohol is the main item of sale and part of the 'nature' of the business.
However, if it is your own business, then selling ‘alcohol’ even as part of the general convenience items is highly questionable as one has complete ‘choice and control’ over what they sell. This is a rather different situation than one from working in a supermarket for example, where you have no control and the ‘sale of alcohol’ is not the main source of the business.
As believers, we are asked to listen to the word and take the best meaning (39:18, 39:55) with a view to make the most appropriate judgment.
I hope that helps, God willing.
Joseph.