keyboard ally

A person who frequently posts pseudonymous comments online in support of a oppressed group, but takes no real world action in their own community where they may face backlash, such that their efforts make no difference at best and at worst encourage oppressors to greater levels of hatred or willful ignorance.

Sara: "Tim spends all day arguing with people on reddit, but he didn't sign that local petition asking for greater police accountability because he didn't want to catch flack from his in-laws."

Jane: "Bah humbug, he's just a keyboard ally."