Some experts claim that values are neither positive nor negative. Others say values are inherently positive, and negative values are simply behaviors that violate positive values.
We can choose to debate these things. We can also agree that we name values as positive or negative so that we can have a common understanding of how we call them.
Nationalism, for example, is often expressed in many ways. But there were wars between countries because of nationalism. Imperialists believe it is their right and responsibility to govern other countries for the sake of their nation. Imperialism is the extreme side of nationalism.
I have mentioned bayanihan as an antidote to kanya-kanya and tayo-tayo.
We have bayanihan because we unite for a common cause. We can say the same for kanya-kanya and tayo-tayo. One group of people unite against others.
This means that some values are more important and beneficial to humanity than others. A value system is negative if practicing them harms others.