To larp is to attempt to act out a fantasy of a cooler life. The protesters were larping as anarchist revolutionaries. In reality, they were rioters and looters. The counter-protesters were larping as a neighbourhood militia. In reality, they were ineffectual dorks.
Not anything done in real life is a larp. It is a larp only if it is meant to be impressive but ends up delusional. To be a prepper or a Twitter Maoist is a larp. To help in a soup kitchen or to canvass for a candidate is not a larp.
Nerdy actions, on the contrary, lack pretence. To study fight choreography is nerdy, to post about studying the blade is larpy.