I think saying each line is a liability is a bit overly pessimistic. At least, to be consistent you would have to say that every line in the entire code base is a liability. That may be true, but it fails to accurately capture the value of the code in the first place.
Nevertheless, I agree with you that I would not call it religious reasoning. When something is implemented in a way that does not follow existing patterns well, or forges a new path, it can make maintenance much more difficult. Given that the original author is rarely available to help with bugs and other maintenance for the new code, it is very reasonable in my opinion to reject changes that Don't conform well to existing patterns, or do things in a way that the future maintainers would not approve of.
A suggestion for people contributing to open source projects: try as much as possible to follow the existing patterns in the code base. It can be a pain to try to learn the patterns, particularly when you just want to add something simple, but it greatly increases the odds of acceptance, and added value in the future. If you want your code to be appreciated by the maintainers, it needs to look like code they would have written themselves. The best way to determine what that code would look like, is by emulating the patterns of the existing code.