Semantics is the field concerned with the meaning of words and sentences. Let's take a look at two sentences.
The weather sure is nice out today
The bourgeois class must be destroyed in order to end the oppression of the proletariat
These two sentences have a semantic difference. And sure, they also have emotional and political differences, but those differences are a consequence of semantics.
The move to brand semantics as irrelevant is a conspiracy by people who don't want words to have meanings. /hj
Look at the way monkeys communicate with each other. They hoot, screech, and throw poo. That's communication without semantics. That communication is pure emotion, no meaning. The people who think semantics doesn't matter are people who wish we all communicated more like monkeys.