Why does WordPress cap the number of pingbacks it attempts per post?

by

The situation for WordPress 5.1:

  1. After publishing a post, wp-includes/post.php‘s _publish_post_hook() schedules the do_pings action for immediate execution. This is put into the “cron” option in database.
  2. Whenever the cron job runs, do_all_pings() is executed, which sends pingbacks for all outstanding posts.
  3. pingback() extracts all links from the post text and sends a pingback to each of them.

There is no limitation to 2 links anywhere.