PostgreSQL not using partial index when using boolean in WHERE clause
Partial indexes make sense when they match the query pattern. In your case if you would have queries with inactive IS NOT TRUE condition then the index would be used otherwise it's simply not useful. 

Cannot use the partial index:

SELECT location FROM pitest WHERE name = 'Anne Lopez';


Can benefit from the index:

SELECT location FROM pitest WHERE name = 'Anne Lopez' AND inactive IS NOT TRUE;