Years later it's still clearly nothing more than a nasty hack.
Sometimes a hack is what you need, and it's the difference between being able to accomplish the goal, and not being able. But key is "years later." Now Citrix is irrelevant, but 20 years ago it let you do things which otherwise simply couldn't be done, and "p0wned" is largely a non-issue when talking about machines not connected to the Internet.
Let's say it's 1994 and you have a legacy MS-DOS application where porting it to Linux or whatever isn't an option. The application talks a lot to a database, and it's fast enough over 10M ethernet. But your medical practice has a satellite office a few miles away, and for a shitload of money, you can get a 56K link. (Yes, these numbers all sound so quaint today, but that's the whole point.) You're not going to have 8 users running that app doing its database queries sharing a 56k link. The patients will die of old age in the waiting room if you do that.
But you put a Citrix box at the main office, which is OS/2 2.0 plus Citrix's hacks, an 8-serial-port digiboard, plugging into a serial multiplexer which plugs into your synchronous mode USR Courier plugged into the 56k link. At the satellite office the other Courier plugs into the demultiplexer and serial lines go to the terminals, and there you go. You've got 8 users at dumb terminals running an MS-DOS legacy app which is really running at the main office where it can easily query the database fast enough. And it works.
Of course it's a hack. But it's a hack that lets you tell the client Yes, we'll take your money and make it work and you'll be able to see patients. That's better than telling them No, it can't be done. Don't you agree?
Ten years later, you might say "screw Citrix, just run dosbox on some Linux machine instead, and connect by ssh over an IP link (or the Internet itself)" and dude, I would totally agree with you. But no fair, you're in the wrong decade, unless you have dosbox working on Linux and talking to Netware servers in 1994 -- and you don't. Believe me, I know, I looked, and you just don't have that in 1994. Or forget dosbox, just port your shitty legacy app to Linux, right? *sigh* Once again, you have my agreeing with you in principle, but it's 1994 and you're trying to sell Linux and you've been pleading for years that we ought to work on getting our app no-longer-dependent on unportable proprietary libraries (and compilers!), and .. holy shit do I NOT miss those days. OMG do I love my new job. Sometimes I forget how much I love my new job and how much crap I'm not dealing with anymore. :-) Fuck you, 1990s. I don't ever want to see the fucking 1990s again. If I'm ever walking down the street and the 1990s are there .. I don't know if I can be held responsible for what happens.