It’s just that the decoy selection algorithm picks decoys in a specific way. Its patterns can be exploited, but don’t stress about it. Churning will make up for it, it’s not that big of a deal. Just avoid spending outputs exactly after 10 blocks as it’s waaaaay more common for real spends than decoys (we can see that the Monero blockchain has way more spends on <20 blocks old outputs than the decoy algorithm proposes), especially when churning. Wait at least a few hours to a few days between churns
I’m just thinking about https://privacyguides.org/ but they don’t really review everything, just tries to give an objective opinion on tools and services that they recommend