It is gatekeeping. The poster was not offering advice, they were being actively discouraging. You can argue shades of grey, but at the end of the day this is an unsolicited discouragement, and an arbitrary out-grouping.
The fact that you don't see this as problematic, is problematic.
There is no gatekeeping. There is a suggestion that C is best used for projects that have builds no more complex than a Makefile configuration. There is explicitly no ~judgement~ limit on what ~kink~ text editor one may use to edit the files.
the fact that they don't see it as problematic means that they didn't misinterpret the comment the way you did, which is because they know things you don't
thus hegemonic institutions reinscribe the kyriarchy generation after generation by perpetuating a hierarchical opposition between "knowledge" and so-called "ignorance", which is socially constructed to be inferior, less than, but which serves the purpose of distinguishing the graduates of elite institutions (to which access is mediated by the financial privilege of the bourgeoisie) from the subaltern underclass; thus "knowledge" serves the interests of capitalism by reproducing oppressive class divisions, enabling the continued exploitation of the working class
what could be more problematic than that?
but if you're interested in learning something and not just playing word games to gain status by putting others down, i problematically mansplained what you're missing in https://news.ycombinator.com/item?id=37083233
The proposed solution of a text editor and makefile is a lot easier to setup than the what's proposed in the blog post, I would call this the opposite of gatekeeping.
What a bad faith interpretation.
It's advice based on the poster's experience, stated with both qualification and good humor. You are free to ignore it. I appreciated it.