If POI pool generation was fully random, there would be repetition. For the same reason that throwing a dice six times will most likely result in repetitions instead of six different numbers (6-sided dice, to be clear). The fact that he said it is not fully random means it will be possible to reduce repetition.
Roland did not confirm that there were repeating POIs. On the contrary, he said he did not see repeated POIs. Here: " I did not see repeating POIs as I have in past alphas."
If he had said there were repetitions, it is still as far as we know a work in progress. There's absolutely no reason to think the first thing that would be done would be ensure no POI repetitions. Or, anyway, reduce them since the number of POIs in a map far exceeds the number of existing POIs.
So as far as I can see both arguments you present contradict your case, and you didn't account for work in progress anyway.
As far as alpha 19 goes, anyway, repetition results from some unfortunate intersection of design choices. Alpha 19 tries to place all POIs before going through any repetition by keeping a list of POIs that have not been placed yet. It also creates cities with zoning and, on top of that, the block size on alpha 19 doesn't match very well with POI sizes. So what happens is that if it tries to place a POI and there's no POI remaining that will fit the space available and zoning it will reset the list of unseen POIs. Whenever that happens, some difficult-to-place POIs like the skyscrapers -- which barely fit a19's city blocks --, lose their priority. In fact, the skyscrapers are most likely one of the main "resetters" as all other Downtown POIs get placed and then the rwg is left with these huge prefabs to fit inside a block that usually already has some other POIs (have you noticed how they are almost always by themselves in a block?). Another likely culprit are the factories: they are HUGE and won't even fit a block. They happen more often than skyscrapers because the Industrial zone includes some stretch of a city border, where they can be placed.
Alpha 19 is a good example of an RWG that is not fully random and has a POI pool generation, and it has these qualities precisely to reduce repetition. It fails to do so not because it isn't trying, but because POIs and RWG were not tuned together to make it likely.