This may have been said before (I'm sorry...I skipped a few pages), but there is an apparent conundrum in the original premise. I think it goes something like this: A person (presumably a new or inexperienced diver) is a "tourist". Therefore, the recommendation is that person utilize a DM until when they dive in order to be safe, at least until they have acquired the requisite experience to be able to take responsibility for themselves. (If I have that summary wrong, please feel free to correct me.)
However the paradox is this: at what point is a person supposed to feel confident enough to quit using the DM? Wasn't that point supposed to be when they earned their cert? Granted, this could be flawed logic too, but there appears to be a couple of assumptions here. The first is that a diver is incompetent and cannot plan their dives and "take responsibility" for themselves on their first outing, hence they need the DM. The second is that diving lakes, rivers and quarries is somehow inherently safer than diving the "big ocean", so that's where a diver needs to do their experience gathering. In my neck of the woods, diving our lakes is, to me, much more risky than "tourist diving". The vis is poorer, there are more entanglement risks, the water is colder, and required gear is usually more elaborate. Task loading can be intimidating for a newbie.
I do appreciate the need for practice and experience in order to make a diver more competent. However, I draw the line at hinting that certified divers are incompetent because they dive infrequently. As long as they stay within their training and capabilities (and I know that could be a big "if") I don't believe they should be the targets of belittlement.