I do NOT want to corroborate with "atheism-plus"Atheists will one day regret consistently repeating this mantra
sure nothing else but a disbelief in "god" is required to be an atheist
but as a social creature that disbelief will come with a cornucopia of social dispositions and many are values we should proudly associated with:
Skepticism
Humanism
Democracy
Justice
Freedom of thought
and Yes, seminally: a respect for the scientific process.
To consistently shrink to this position in order to defend atheism from being ascribed negative qualities is to fall for the jedi mind trick, and to remove from the public imagination, the relatabe and affable diversity of implications that atheism comes with, and to leave a dark corner from which charlatans will rise and redefine atheism for you.
Lets keep it simple and stop trying to make atheists, liberals.
Other terms already exist for what you're describing.