Very very true and maybe not only in connection to gambling, but with other human relations too. Recently I have learnt that kids in school can be very mean to each other online in social media, while the facade they maintain in real world is that of complete normality. My understanding is very similar to yours: that is much easier to be mean online, because you are sitting in front of the computer and do not have to confront other humans and their emotions and on top of that your emotions either.
I think they are just kidding around. Online, I also talk like that to my friends but we know well that we're just fooling around and we're doing the same thing to each other. But that doesn't mean that we're actually mean to each other. Anonymity gives us power and shy people can also have their time online since no one can see them. You even see shy people being famous online because they get to interact with people without having to show up, without having judged. It's all just in text form. Thus, shy gamblers can just be powerful when gambling online.
Real people cannot be trusted at all times, there were situations that they betray us through cheating the gambling games. Land based casino was preprogrammed and has monitoring cctv, at first they'll attract you with rewards and lucky bets. But in the next successive days to come your bets won't work out, because you've already spotted out and recorded to the monitor of the casino's establishment. Unlike with online gambling, you can do your will as you wanted to eventhough you're shyness doesn't matter as long as you're knowledgeable with the games online.
I'm not entirely sure if that CCTV monitoring thing of each person is an actual thing. It's just so much work if someone's going to remember everybody's faces and then rig whichever table they go to and not rig the ones where newbies are playing. It's so much work that I don't believe it entirely but for the discussion, let's suppose it is. Doesn't it make perfect sense to just go to different casinos instead so you're always going to be a newbie? After gambling in a casino and noticing that it's become hard for you to win there, just gamble on a different casino and then voila! easy winning bets again. Rinse and repeat.
But then again, I don't really believe that you easily win at first and then it becomes harder because they are rigging your table.