A classic fanboy-type argument has real-world tax implications. If the IRS decrees that Marvel's comic book mutants are human, then Marvel will have to pay more taxes.
In the non-fictional world, our world, Marvel is taking the position that mutants are not humans at all. But this isn't an ideological or a moral stance. Instead, it is a financial one. Toys manufactured in other countries and imported into the US are subject to taxes, but those taxes are lower if the toys represent non-human characters. That has led to Marvel lawyers arguing that an action figure representing, say, Wolverine, is actually "representing animals or other non-human creatures (for example, robots and monsters)." This argument leads to a good conversation on the questions of humanity and acceptance that have long been part of the X-Men storyline.
Perhaps Marvel can tape a small styrofoam cube to its characters to skirt the rules.