What is the purpose of your comments? You failed to answer his question, then attack him for asking the question. Consider the two possibilities: a) doing that homework is easy, b) it's hard. If it's easy, you could have just posted the relevant link and be done. If it's hard, then his question is warranted. Either way, your comments add nothing. One can only conclude that you don't actually know how to answer the question. The real question, though, is: why even bother replying?
Also, ReBAR can get complicated as you can see from other responses above. The articles on the web are also not really good as they tend to replicate marketing material and make vague statements about performance, but fail to explain how specifically performance is improved.
They wanted a basic explanation in response to that.
Or to put it differently, I would take the sentence "He asked for a purpose and a use-case not an explanation." and replace the word "not" with a comma.
The sale of the hammer to a sanctioned group would violate export controls and other regulations. So yes, it is your fault.
In this case these guys are providing a service, so I would wonder what they are doing differently than, say, Facebook. The latter is also used (and run) by criminals. Most likely the governments want this particular service down, found the legal avenue to do so, and are now following through.
