"Gang motivated" is a term used in a style of reporting that accounts for only those crimes committed by gang members wherein the gang as an entity profits. It is basically gang vs. gang assaults that account for most "gang motivated" crimes. Most gang crime against non-gang members is seldom tallied under this system.
The absurdity of this style of reporting is that it assumes gang-motivated crimes are the only crimes gang members are capable of committing. To really track gang crime, the gang's activity must be measured by all of the crimes committed by its members. Gangs are not top-down paramilitary organizations with leaders that dictate all of their actions. The gang as an entity does not commit crime, its members do.
This is why most law enforcement agencies have opted to use the style of reporting referred to as "gang related." In general, any incident involving a gang member as suspect or victim, particularly if the subject is a victim due to his gang affiliation, is counted using this style of reporting. This provides for a consistent and complete report on gang member-involved crime, and it minimizes subjective decision-making by officials.
But politicians don't like to use the gang-related style of reporting because the gang-motivated concept yields a sense of accomplishment. They can also cut back on spending in the affected area and boast of their accomplishments, which does nothing to prevent the gangs from doing their thing, which is to terrorize their communities.
And gang activity does not necessarily cease with the prosecution and incarceration of the offender. So proper identification is important for jail and prison officials so they can take steps to ensure the safety of the inmate and others in the inmate population. The standard gang accounting system within the corrections system is based on security threat groups, not necessarily gangs, which may or may not qualify as an STG. Therefore the system does not always agree with those used by law enforcement agencies. Correct counting of gang members is about decreasing the number of toe tags handed out in morgues inside jails and prisons and in the community.