Taking fiction aside, if there were a real-life non-lethal vigilante, how would the criminals they catch legally go to prison? The vigilante broke the law to gain evidence, so all the evidence the vigilante obtained would be thrown out, and every criminal would walk. As messed up as it is, The Punisher and Dexter make sense, because the only way a vigilante can really be successful is if he just straight up kills the criminals.
The laws would have to be adjusted in a world where vigilantes exist. This is actually a plotpoint in several vigilante stories. Either the (super)hero catches someone and they can’t go to prison or the laws have to change in a society where superpowers exist.