In declaring 'Black Lives Matter' the speaking selves, not just the speech acts, are performative. In these acts, individuals seek to transform the value of their own lives, explains Judith Butler. 

I am not sure that I would defend the thesis that the self is performative, although that position is sometimes ascribed to me.  The reason for my hesitation is that the meaning of performative is highly contested, so I would want to wait and see which meaning of that term is in play when someone makes that claim.  Further, I am fairly certain that whatever the self is, it is not exclusively performative.  So though there may be performative dimensions of selfhood, it would be too general to claim simply that the self is performative and that is the end of the story.

I notice that very often “performative” is used with the adjective “merely” so that when we hear that someone has taken a stand and that it is merely performative, we are meant to understand that this is a gesture of some kind, but surely not substantive.  I am not sure why gestures are not substantive (I think Brecht would argue that they are), but the “merely performative” is itself, well, a gesture which is meant to discount or devalue whatever is being described.