Arguing that there are many bad things in the world and that geek feminists should be spending their time on those is a silencing tactic. Examples range from systemic food shortages to Microsoft's activities in the software marketplace.
There is one particular case of this which is problematic: allegations of intersectionality failure. Feminism often merits criticism for perpetrating racism, homophobia, transphobia and other oppressions and such criticism is not silencing. However, the form of it that amounts to telling a feminist forum that "we've talked way too much about gender issues here, I think we should solve race issues instead" is. This is sometimes disingenuous, coming from critics who are not themselves active in any diversity or anti-oppression movements and don't seem to have any motive other than ending the conversation.