The section mentioned is in Part 11 of a County Land Implementation Program for MDR that was approved by the Coastal Commission.
If you read further back starting at 22.52.1000 you will find that when someone builds in MDR, they are required to provide sufficient parking for their structure to assure that an adequate number of spaces are available to accommodate anticipated demand and not create competition for on-street parking or that would infringe on others parking facilities.
In furtherance of that goal, 22.52.1010 says you cannot take a parking space out of service (convert your garage to storage) unless you first replace it with equal, off street parking that meets the requirements of Title 22 of the Land Implementation Program.
In short, you need to clean out your garage and move your stuff somewhere else, or buy up immediately adjacent land, get both LA County and Coastal Commission approval and build a suitable replacement garage.

