On his first trip to Cuba during his third term in office, Brazilian President Luiz Inacio Lula da Silva called the embargo imposed by the United States on the island "illegal" and denounced the island's inclusion on the list of state sponsors of terrorism.
If every state except two in a supposedly democratic body made and controlled entirely by said states is of the opinion that something is illegal according to that body’s own laws, and have voted upon such language every year consecutively and similarly unanimously for decades… then is it not? And if not, does it matter?
Again though the UN could enthusiastically support it and it would still be every bit inexcusable. There is no further value to discussing whether it is “legal” or not.
Your initial claim that I responded to was that the UN declared it was illegal. I am correcting your misunderstanding on that regard because despite your claims they never have declared it illegal.