Whether that is an accurate depiction and if the response is legitimate I will leave for more knowledgeable people than myself given that it is a fairly tricky legal question. The ban on attacks as retaliation is however quite clear and the claim that a right to retaliation exists is false. If you want to learn about that you can just have a look at the UN charter and its ban on attacks. Of course the attacks in Syria attributed to Israel are likely to be just as illegal as any retaliatory strike would be.
15 police officers killed in Colombia helicopter crash (Reuters)
from the article: Time for Israel to do a little warmongering in Syria