The max RAM that the 2010 mini can take is 16 GB.
Why do you say you can put more memory in some machines than Apple does?
Apple sets their maximum memory configuration based on the memory modules available at the time of the product's release. Apple does not typically revise this limit as compatible higher density modules become available after the release date. This is a safe policy to follow but it inevitably causes confusion when memory vendors and dealers (and Mactracker) state that a computer will hold more memory than Apple says it will.
source: Mactracker