Why do people say "пинать ногами" when the act of "пинать" can only be done by "ноги" and nothing else?
Such redundancy is called
плеоназм (an link for the English article) and in natural speech there are lot of examples of phrases that can be shortened without loosing any information. In the link provided above there's another example:
- «Он сказал мне [о том], что его приняли на другую работу» (what is in square brackets can be omitted).
А где это находится географически?,
героический подвиг and I can go for quite a long but you got the idea. As you can see, some of such usages a de-facto used quite often - that often that you don't even think about such redundancy.
Good editor is supposed to recognize such phrases and get rid of them though.