This Gall-Peters crap is worse than a chain letter; it just keeps coming back and will not DIE. It's a horrible projection. If you need area equivalence, there are far better equivalent projections (Mollwiede, Hammer). If you don't need strict equivalence and just want a reference map than balances out distortion, there are hybrid projections well suited to that (Robinson, Winkel Tripel). Modern wall maps used in classrooms are generally based on hybrid projections, not Mercator. National Geographic uses Winkel Tripel for instance.

Peters hand his followers place far too much emphasis on area compared to other properties, they use a straw man argument by always comparing to Mercator maps rather than actual modern ones, and even allowing all that, the solution they propose is a BAD solution. Gall-Peters distorts shapes so badly that it's pretty much unreadable near the poles.