If only 1/5th of those prisoners are there for drug-crime (and I assume you believe as I do that much drug-related crime isn't worth the arrest?) then isn't that in fact evidence that our population commits substantially more _real_ crime than in other countries?
If so, then yes, let's lock them up. "Everyone steals" is not a good defense to stealing.
If so, then yes, let's lock them up. "Everyone steals" is not a good defense to stealing.