My experience, most "dead weight" employees tend to be quiet types who never rock the boat. They want to just keep flying under the radar. They say please and thank you, they show up to company events, but just.... don't produce. Which can make putting them in a PIP extremely awkward because you feel like the bad guy.
Meanwhile, the most proactive "complainers" I've worked with have all been median to high output engineers. As a manager, I find my approach for them is to try and get them is to mature socially inside the org and work to break them of their bad habits. Results are mixed, but I've had some success.