Why do gamers/players think making a custom engine makes a game inherently better?

I don't understand this argument having made games across different engines. It frustrates me a little bit, and offends me as well. A general sentiment I see is something like "All games in Unreal look the same". That is not really the engines fault, that is of the artists and designers. All in all isn't an engine just supposed to be a tool that enables you to make games more efficiently? Why would you need to build a custom engine if your game could be made in Unity, Unreal, Godot, or even something like GameMaker?

For example, if you use a pre existing engine, you're saving time and now you can focus more on game mechanics, artwork, story, design, or music/sound.

Some people may enjoy the process of making their own engine and that's fine. But I feel its wrong to put down projects, companies, or indies even for using an engine.