Dish soaps are chemical surfactants; fruit washes use plant and animal based surfactants.
Can the former (dish soap) be used as the latter (fruit wash)?
Yes. Use it exactly the same way. In the same way that the best thing to do with fruit wash is leave it on the shelf in the supermarket, the best thing to do with dish soap (when it comes to cleaning fruit) is leave it in the sink cupboard.
Both the U/Maine article referenced by the top answer at Some Other site and the BHG article you reference are clear: Use water to wash your fruit. The U/Maine article includes soaps in what to not wash your produce with. Body soap (if that's what they mean) is closer to fruit wash than dish soap and is still not recommended for washing produce.