This IMHO, is a major Filipino trait. Being regionalistic is also one. For example: you usually get special treatment from people who are your 'provincemates'. This sort of trait extends to who belong to what school, and what may have you.

Now this is one reason why Pinoys can never be united. May sari-sariling tropa kasi. Ayan may sari-sariling diskarte. Mine is always better than yours.