The use of whole clusters in Pinot Noir fermentation is an ancient technique (what else did you do before the first destemmer was invented in the mid-1800s. Yes, you could destem by hand – what a PITA). Now, winemakers have a choice – to destem or not to destem? Some winemakers destem all their fruit (Henri Jayer was a famed proponent of this in Burgundy) while others use 100% whole clusters in all their ferments (Dujac in Burgundy was a proponent in the past). And, then, some winemakers choose a middle path between the two.
Here’s a great article with multiple winemaker inputs on the topic: https://www.princeofpinot.com/article/865/