In the same way that magnetic toys are a novelty that can cause injury or death to young children, vitamins that look like candy (but is treated like prescription medication: packaged the same and stored in the same place. Treated with the same paranoia by parents.) and candy that looks like prescription medication (think: tick-tacks) cause harm. Specifically they cause harm by contributing to confusion between candy and medication among children.
They specifically call out parents calling medication "candy". This is apparently something that parents do with enough frequency to warrant calling out. As far as I am concerned, candy-like vitamin supplements are no better.
I would suggest that prescription medication manufactures stop making medicine in bright colors and fun shapes, however I suspect the harm done by such a suggestion in the form of accidental adult poisonings would outweigh the benefits.
I would therefore argue, were I inclined to, that candy and vitamin companies should modify their products. I would not advocate prescription medication companies altering anything.
So my thesis: confusion between medication and candy kills thousands of children every year. There are trivial things we can go after in an attempt to curb this phenomenon (to repeat: tell vitamin and candy companies to knock it off). Nobody is calling for these trivial measures, even though they seem greatly concerned about a problem with much smaller magnitude. The reason for this incongruity is that candies and vitamins are familiar, while magnet toys are new and striking.