I apologize in advance if I cause offence with this question, but I am curious about these two terms.
反日 can be translated as “anti-Japan(ese)”. I have seen one example of this term being used to refer to the education system of South Korea. I have never lived in South Korea or Japan, so I don't know if the South Korean education system is truly anti-Japanese. Also, I have seen a question on a Japanese Q&A site asking what 反日 meant, because the questioner was accused of this for advocating the abolition of the death penalty. I suppose the death penalty is a sensitive topic for some people.
日本たたき can be translated as “Japan-bashing”. It seems that if you criticize something in Japan on the Internet, someone will accuse you of this. Personally, I think there is a difference between pointing out an issue in a country and using a country as a punching bag.
Like I said, I would like to know if there is there is a difference between the two terms. They seem to have a connection, but is it possible that they are used for different things? Thanks in advance!