Just curious: what's unsafe about creating a text file using the GUI?
Probably nothing, but it should be noted that:
1. SK made this remark with respect to GUI vs command line tools in general, not text editors, and
2. The spirit of your question implies the reverse of what SK said. To paraphrase, SK said GUI's are great in cases where the command line equivalent might be slower, "worse" or dangerous.
An example to illustrate the point: unless you really know what you are doing it is better to drag a file to the trash in the Finder than to invoke the "rm" command in Terminal. The former allows you to recover from a mistake, the latter is less forgiving. Hence, the GUI is safer than the command line.