This tactic of appropriation for political ends is sometimes referred to as entryism, and while it's not confined to any one ideology I think the right is somewhat better at it because it's consonant with the idea of machtpolitik and gaining territory by seizure. Given the difficulty and costs involved in contesting physical territory, securing virtual territory (from dominating a forum to 'owning' a particular word or phrase) is a necessary precursor to control of a larger battle space.