No doubt that tons of biased decisions are made in the games industry all the time.
I think the bias against Nintendo in particular has more to do with Nintendo not pandering to and including 3rd parties as much as Sony and MS do. They often hold their cards closer to their chest than any other player in the industry. This leads to 3rd parties feeling left out of whatever Nintendo is doing.
When Sony was making hardware for 3rd parties they asked 3rd parties what they wanted and needed. When Nintendo made a console for 3rd parties they made what they thought 3rd parties wanted or needed. Because they didn't ask and share they ended up with a console for 3rd parties that no 3rd party would touch.
Being the manchildren that most 3rd party developers are they exclude Nintendo because they feel they too have been excluded. It's all rather childish really.







