The cited answer is one to which I applied the post notice and, in its current one line state, I think it should be left there.
I almost always process the system generated flags on one-line answers by applying a post notice, irrespective of who the poster is, so that it is the answer, rather than its poster, that is being assessed.
The exception is when I see a one-line answer that I know can, if I have time to, be expanded via an edit.
For example, a one line answer to a question about which tool to do some ArcGIS polygon overlay operation might be:
Try using the Union tool
which would normally get a post notice for being a one-liner, even though perfectly correct.
However, it only needs a simple edit to become something like:
Try using the Union tool which:
Computes a geometric union of the input features. All features and their attributes will be written to the output feature class.
With minimal effort, it changes the answer from being a bare instruction, to one wrapped with a summary of what it does and a link to where more information about it can be found.
I would recommend doing something similar to any one-liners that you see with post notices, if they are within your area of expertise, then flag asking for removal of the no longer applicable post notice.