calamares depends on dev-libs/libpwquality[${PYTHON_USEDEP}]. I suppose it does need the python bindings, but then it must also depend on USE=python with dev-libs/libpwquality[python,${PYTHON_USEDEP}], or python bindings may still be missing and things are broken. tl;dr: $PYTHON_USEDEP without USE=python dep don't make sense for a libpwquality dependency atom.
Looks fixed by someone in the meantime.