No, that's not correct; you do not need to have IPFS installed locally in order to post to DTube. DTube uses IPFS to host the files, but it initially seeds the videos itself. When you upload a video it goes to a central DTube server and they host the initial IPFS seed of the video. If you have access to an IPFS server, you should "pin" your own videos there, which will help with seeding/distribution, but it's not a hard requirement for even uploading your video.