And yet lobste.rs maintains a high signal to noise ratio without HTML from the 1990s. Proper moderation has far more to do with maintaining the quality of the community than using tables or raw font tags. I would even argue that some features of the current layout contribute more noise than signal - to give two often argued-over examples, non-collapsible comments, or the fade effect of downvoting.
Some features (or lack thereof) can possibly be justified in the name of intentional simplicity but not everything. How the table-based layout keep the signal to noise ratio up? It doesn't, it can't.