So the counter-argument is that the CO2 that remains in the wine protects it and reduces SO2 requirements. I've seen this in a few places - most notably the Beaux Freres website
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). Most of my research has been around pinot where the cool kids seem to age on gross lees and never rack. I understand this is dangerous (as I've experienced with a barrel of syrah), but the argument is that the lees does improve the wine. Like most of winemaking I've found that there are always two contrary opinions from people whose opinions I respect. It's quite maddening.