no, it isn't what they mean. you might say it's "equally" sexist, but "man" meant "mankind", it meant "person", and woman comes from "wifeman", person who is a wife. So mailman is "person who delivers mail". A good way to think of it is that language is actually neutral. Cultures have ideas and values, and those ideas and values suffuse communication, but the language is just a transport mechanism and will be bent and altered to communicate what people are thinking. But the language, always neutral.

it's similar to the names of native american tribes. There are so many examples of "the Sioux didn't call themselves the Sioux, they called themselves Lakota, their enemies called them the Sioux." What did Lakota mean in Lakotan? It means "the people". Everybody else? they weren't even people. Every native american tribe did that, and probably our own hunter gatherer ancestors did that too.

None of this is cause for concern, it's actually really interesting.