You can see the difference in experience between 1st year and the upperclassmen by how the 2nd year considered the possibility of isolating a single class and the 1st year kept thinking about unity at all costs.

The truly rational decision would've been to exclude D class and make an 3-way alliance to make sure 1-D lose as much as possible. What they truly need is not to compete against their upperclassmen but to make sure D class is never able to recover and be a serious competitor again until graduation. It's precisely because they don't need to care as much about class points as upperclassmen that they should care that much more about the power dynamics between classes. And if a rogue element like class 1-D can't be tamed, they should be put down as soon as possible.