The guys on the call are Republicans that were trying to do their job. As for why the call was released, Republican Brad Raffensperger, the SOS for Georgia has been the target of misinformation and distortion. He chose this time to have a record of the conversation. He did not release it until Trump tweeted more distortion the morning after the call.
As for being cowards, they have been receiving threats to themselves and their families. Yet they are still doing their job according to Georgia law. I'd say brave micki-fickees.