What you are experiencing in this case is something I have described as the "birds of a feather" syndrome. Birds of a feather really do flock together, so people who are used to expressing ideas in front of friends and getting universal approval are sometimes surprised when they step out of that normal circle and find that there is a significant portion of the world that does not agree.
A former major league pitcher from the deep south, John Rocker, made the kind of comments he was used to making all his life the first time he was interviewed by Sports Illustrated, and he was shocked by the country's reaction to his perceived racism. A UCLA student posted a Youtube video about the way Asian students talk in the library that her friends evidently thought was hilarious. After the video went viral and the world reacted differently to her racism, she dropped out of school.
We had a situation like this on ScubaBoard a while ago. After people started diving the wreck of the Oriskany off of Pensacola, FL, a man accustomed to diving wrecks off the New Jersey shore headed down with all his tools and took out a major communications system. He went online and bragged about it, thanking the captain of the boat that took him there for his help. In New Jersey, taking everything you can from wrecks is part of the culture, but for most of the diving world, it is just plain wrong. In fact, in the case of the Oriskany, it is against the law. (I believe the captain tried his best to pretend he had not helped the guy break the law.) The resulting thread was a humdinger, with the "take anything you want" crew and the "you saw it--leave it for others" crew yelling at each other with no resolution. I think each side in the debate was shocked to learn the other side existed.
The same thing is true for what you did in this video. There are people who think it is perfectly fine to harass sea life, but there are many who don't like it at all, and they will not be shy about telling you that. I am one who does not like it at all myself. I once started a planned dive week with Big Island Divers in Kona, Hawaui'i. On the second dive of the first day of diving, the DM manhandled an octopus the way you did, producing about the same amount of ink you did. I switched to a different operator for the rest of the week, and I made sure I mentioned in on ScubaBoard. In fact, I mentioned it a number of times on ScubaBoard. This is probably the 10th time I have written that the DM at Big Island Divers in Kona manhandled an octopus that way, and I will bet they have lost thousands of dollars of business because of it.