Activate short codes for all post queries?

There is a way to apply that to all post content.

function sc_all_content_wpse_137734($posts) {

  foreach ($posts as &$p) {
    $p->post_content = do_shortcode($p->post_content);
  }

  return $posts;
}
add_filter('the_posts','sc_all_content_wpse_137734');

I would suggest that this is a very, very good way to break things. Plugins and themes will not expect shortcodes to be rendered that early, and the code above will break shortcodes that depend on the $post global, though that could be gotten around with setup_postdata.