One may get involved in activities with negative OR positive connotations. The phrase get involved is entirely unrelated to the subject matter to which it is applied. A few examples of involvement in situations that are perceived as having less social merit, or deleterious to an individual's well-being:
People get involved in the illegal drug trade because it is lucrative
He might get involved in fraud
Of course, one may get involved with a civic society, a charity or volunteer organization, church group, advocacy effort for the disenfranchised, or a new coding project, all of which are positive.