what surprises and annoys me is Briton's willingness to name their children shortened versions of existing names, it's lazy, so many Archies and Alfies, ugh.
Regardless, I'm glad you're averse.
(Mind you, the UK is still worse - Jack is #19 but John isn't even on the list)
Doesn't really matter, I suppose - names are pretty arbitrary anyway and I can't imagine the sort of pain that would be involved in trying to force-canonicalise Jack->John, Leo->Leonard, Theo->Theodore (or Theobald?). Even the French don't do that any more!