Are you saying that the reaches and fit should be different or that they should label the sizes differently. As a 188cm person, the XL is a perfect fit for me. Their ETTs for each size fit, their seat tube lengths are for sure within what I would call as industry normal. Arguably, their ETT's are a touch shorter, by about 10mm then what most brands are doing size for size.
When it comes to sizing, the only way you can be certain is to try not only the bike you're considering buying, but many, many bikes. Through the course of demo'ing bikes over the years, I know the exact fit dimensions that work for me and I completely ignore the recommended sizing.
Depending on the style of bike, or my intended usage, I vary those targets slightly. For example, I prefer a 490-500mm reach on my enduro, dh and long travel ebikes. However, for a trail bike where I won't be doing as large of features, going as fast and doing a lot of seated cornering on meandering terrain, I prefer a 480-485 reach. That shorter reach leaves me feeling more on-top of the bike then in the bike, and I can get a slight front wheel tuck sensation on steep bermed corners.
For me, the Santacruz sizing is literally perfect. It's actually one of the reasons I keep going back to santacruz after going to orbea, giant, or transition. Those brands have a Large that's slightly to small for me, but an XL that's slightly to big. Santacruz keeps a very consistent and regulated jump in reach/ett/stack/sta between sizes, and they target average height riders with the medium/large models well. My only complaint would be a touch longer chainstay on the XL and a bit more stack... but I can cope with one and adjust the bike for the other.