The best explanation for why a shoe and a shirt take different amounts of time to fall to the ground, assuming they are released from the same height, is:
The weight is equal on the two objects, but there is more air resistance on the shirt.
This statement aligns with the principles of physics regarding how different shapes and materials interact with air resistance. The shoe, being more aerodynamic and compact, will experience less air resistance compared to the shirt, which may flutter and create more drag as it falls. Thus, even though they might have similar weights, the differing effects of air resistance lead to different falling times.