BuddyPress.org

Solution: credit to @lincme on the post https://buddypress.org/support/topic/filtering-out-activity-stream-stuff/

// Remove (hide) various activities from streams.
function my_hidden_activities($a, $activities) {
	//if admin we want to know
	//if (is_site_admin())
		//return $activities;

	$nothanks = array('activity_comment');

	foreach ($activities->activities as $key => $activity) {
		if (in_array($activity->type, $nothanks, true)) {
			unset($activities->activities[$key]);
			$activities->activity_count = $activities->activity_count-1;
			$activities->total_activity_count = $activities->total_activity_count-1;
			$activities->pag_num = $activities->pag_num -1;
		}
	}

	// Renumber the array keys to account for missing items.
	$activities_new = array_values( $activities->activities );
	$activities->activities = $activities_new;

	return $activities;
}
add_action('bp_has_activities', 'my_hidden_activities', 10, 2 );

I took a very hacky approach to the activity-loop.php

changed:

			<?php bp_get_template_part( 'activity/entry' ); ?>

to:

		<?php if(bp_get_activity_type() != "activity_comment"): ?>
			<?php bp_get_template_part( 'activity/entry' ); ?>
		<?php endif; ?>

This will almost guaranteed cause problems in the loop keeping track of how many activities there are to display.