Well to be fair he didn't put it out himself - on the other hand he didn't ask for it to be taken down or ensure that the video of him surfing was not published. There's one of three options as far as I can see.
The guy who published it is the surf instructor - his whole Instagram is lots of these videos of his students learning to surf - when they are little kids he is often right next to them on a second surf board holding them up as they surf. I actually started following him a couple of months ago after seeing one of his viral videos by accident. He's a fabulous teacher and a good surfer - but he's got a huge beer belly which surprises me because I'd have thought all that surfing for his job would have kept him very trim - his core strength is impressive when he surfs.
Harry took a lesson with him knowing that it was common practice for the instructor to film and publish part of the lesson so I think either
He got a great deal or free use of the wave pool and lesson in return for letting the video be shown,
He actually got paid for the promotion the video would bring to the business
or he thinks he looks quite cool so he doesn't mind the video being out there.
But I don't think he specifically asked for it to be posted.