Unfortunately people are not all that great at moderation and a complete lack of measures means industry and infrastructure will be built to support the insatiable demand/addiction. A lot of humanities resources are utilized supplying said demand. There are the health and societal consequences which everyone as opposed to the individual end up paying for.

Mostly its the intricate web of consequences we yield when chalking everything up to personal choice and being smart about food decisions. Sooner or later people peddle worse and worse substances that satiate the desire but for cheaper like re-purposing industrial runoff or former waste products in the production of some other foodstuff. This partially offsets losses as you sell waste product with no other purpose you would normally need to spend money to properly dispose of.

Sugar is not so wildly needed by anyone that it would rank with other freedoms, you would want access but not unlimited, unchecked access.

Those with self control don't suffer under limited environments as its effectively no change for them; they were not over-indulging anyhow. Unless they were invested in the industry, at which point we're back to robbing the whole as this could have been invested pursuing other things that serve the whole better.

"smart" people aren't going to want the "freedom" they weren't utilizing anyhow because of the high cost associated with no limiting measures in a specific segment of economy.

Do you want another sweet factory or at some point is there a better use of human time/resource than adding the 4,000th confectionary manufacturing line.

On the flip side, there are few things people are willing to pay for outside healthcare and dental and sugar wrecks both of these things. You can pay people more as a larger portion of their pay is spent on healthcare and dental work which de facto helps build these industries up. In turn the economy is strengthened in a far removed way of effectual taxation where money eventually ends up pushing forward a prominent industry which is exported to the world (medicine, medical devices)

Similar to when someone purchases a personal boat or plane money is going into the industries in part furthering research and development of boats and planes.

Its a little more complex than muh freedom or profiting off the 'dumb ones'