Really interested to read the answer to this question :-)

Like it - hope a pro answers. Just guesses here: Maybe the lally columns are wrapped in something - and that wrap is omitted where the wood shelving is? (I.e., the black finish we're looking at is on top of the support pipe.) Or perhaps a thin but strong flange is under each of the 2 shelves (around the black pipe, under each wood shelf?) Here's an inexpensive flange holding up a small wood table around a lally column - I'm sure with $$$ and custom metal fabricator, a much narrower flange could be bought or custom made. (Ok, the url didn't work out - just google basement pole drink shelf Etsy to see what I mean.)