Personally, I think this is a strength of StackOverflow. I think most people read through all of the answers, and this particular one keeps people who know nothing about regex from trying to evaluate regex with regex.
And for those with a deeper understanding, they have an answer that provides the intellectual stimulation they are looking for.
> I think most people read through all of the answers
You're vastly overestimating what most SO users come to the site for. They (and I include myself) just want something that'll work and isn't horrible. Even "not horrible" is something I care about but I know that many devs don't.
If somebody doesn't know the answer to their question in advance, which by definition they don't, it's by no means guaranteed they will know a horrible answer when they see it.
And for those with a deeper understanding, they have an answer that provides the intellectual stimulation they are looking for.