[Plugin: Events Manager] Set the name of the event contact person as WP user profile link

thanks for sharing your solution

update (for EM 5.1.3):
place this code into your functions.php

the placeholder is called #_JNZCONTACTURL

add_filter('em_event_output_placeholder','jnz_author_url',1,3);
function jnz_author_url($replace, $EM_Event, $result){
	global $wp_query, $wp_rewrite;
	switch( $result ){
		case '#_JNZCONTACTURL':
			$replace = get_the_author_meta( 'user_nicename', $EM_Event->event_owner );
	}
	return $replace;
}

please note: this only pulls out the author slug, not any “authors” or whatever custom URL structure..