> That's common on linux. Many tools read from stdin if a file path isn't given: cat, xargs, base64, cksum, etc.

No. I did pipe to stdin. It's not my first time using Linux...

Here's a command line I ran right now, and the output I see:

  $ echo "http://www.example.com" | parallel -k -j 8 curl -s "{}"
  Academic tradition requires you to cite works you base your article on.
  [...more nonsense...]
  To silence this citation notice: run 'parallel --citation' once.
  
  parallel: Warning: Finding the maximal command line length. This may take up to 1 minute.

So I wait a few seconds... until I get fed up and look at my process list, and I see perl is just... seemingly sitting there, doing seemingly absolutely nothing. I'm not going to waste a whole minute of my life waiting for this; I see no reason competently written software should take that long just to accomplish such a simple task where nothing is remotely close to reaching any limits.

So I Ctrl+C. And then the parent perl process gets killed, but the child apparently keeps running.

I press Ctrl+D to exit the terminal, and then:

  $ # (Ctrl+D pressed)
  logout

...it just sits there waiting. Ctrl+C and Ctrl+\ do nothing. I have to kill the lingering perl process manually.

xargs Just Works without any of this nonsense, yet somehow I'm the one holding GNU parallel wrong?