Why so salty? His game will probably have a fraction of the resource requirements of the overkill, overbloated, kitchen-sink engines written in C# and C++. I would command this author for not going the easy way. This takes skills.
Because most folks on social media that suggest replacing engine X with Y, mostly reveal a complete lack of knowledge of what engine X's capabilities, market presence and synergies, or why studios pick it in first place.
You'd be surprised to find most studios pick X over Y because it's either familiar to their devs or cheaper. Better doesn't really play into it and a thorough evaluation beforehand isn't usually done.
As former IGDA member no wouldn't, however most of studios don't pick a raw graphics C library versus proper engine, unless its their first title and don't have any clue about the games industry.
Funny enough, during my 30 years (give or take) career I have seen many more game projects fail using Unity than projects using cobbled together inhouse engines. It's always the team that counts, not the technology (the technology just always gets blamed when the team fails to deliver, the actual reason is usually organizational).
That absolutely works for many 2D games where Unity is currently used just because it is the "industry standard" but is also complete overkill.
Sure, if one wants to write games like in the 16bit glory days.
One of the benefits of doing something as a hobby is that it doesn’t need to scale.
That isn't the scenario we are talking about regarding RayLib versus Unity, as mentioned by OP.
I’m happy for you to code your game however you want. I like doing it this way.
Sure, good luck with it, not everyone needs Unity, Unreal, Godot, Frostbite, CryEngine,...