"Invisible" Links Removed From Post

Black Hole

May contain traces of nut
In THIS POST, there were links to an Amazon listing for the Firestick, but they were invisible (and unclickable) due to the anchor text being whitespace.

So far as I can tell, the OP should have been able to post links having been a member for 5 years and having more than 20 posts to his credit, but now the mods have removed the bad formatting (including the links themselves), including in my quote of the post further down the thread.

Either way, this raises questions:
  1. If the OP is permitted to post links, why did the mods remove them rather than correcting the formatting?

  2. If the OP is not permitted to post links, how did it fool the forum software security? And why not, as the links were clearly innocuous, just let them stand (corrected)?
What is the current threshold?