If we have the alarming realisation that we’re actually rooting for these characters, it’s because we’re being cleverly manipulated into doing so by everything that’s happening around them. They might be sex criminals, con artists and gangsters, but the world that’s created for them to battle against is such that we overlook their deviancies in spite of ourselves.
Joe from 'You' is a great example of this, and Deadpool, although I would argue that Deadpool may have grown more as a character and is less 'villainous' in his traits than when first introduced, he's very loyal and helps people who are innocent and deserve help, but he still makes crucial errors in his judgement that have tougher consequences than 'traditional heroes' and can seem selfish, which is why he is defined as an anti-hero. This observation is based on the movies as opposed to the comics which i need to read.
