You need to make it clear "Girls Who Code" has nothing to do with this shirt.
"We intend to give the money to Girls Who Code. In the event that they do not accept the money we'll look for another charity that supports women in tech."
While I firmly stand on the side of the poor bastard who got fired for making a simple joke, I find it distasteful that a bunch of guys would design a shirt making fun of the situation and then donate the money the a charity that "supports women in tech."
If Girls Who Code actually made the design, it'd be different.
Instead, this feels mean-spirited.