For starters, how the fuck do you enforce an embargo without the threat of violence, and secondly I love how me and all my communist friends are expected to have a PhD in world history and economics while your average liberal can cite two state department links and a CIA funded NGO and call it a day.
This is an excellent example of one of the ways that moral progress has actually reversed in the last few decades. Even the compararively barbaric European and American politicians of the early 1900's all understood and accepted that economic sanctions were a form of actual warfare.
I remember reading an analysis I liked from somewhere a few years ago saying that this phenomenon is because the "old money" of the 19th/early 20th century who knew where their value came from (the labor/exploitation of the working class & the third world) and how it related to class warfare and their position in it have all died out, and now all that's left are "true believer" heirs and sycophants of that old money who don't actually know where any of their surplus value comes from. To me, anyway, that may explain why everything is so much more nonsensical these days from the wealthy/ruling classes.