Reall? Libreoffice at least has a File > Open menu that allows you to specify the separator and other CSV stuff, like the quote character

You have to be inside Excel and use the data import tools. You cannot double click to open, it outs everything in one cell…

Sometimes you double click and it opens everything just fine and silently corrupts and changes and drops data without warning or notification and gives you no way to prevent it.

The day I found that Intellij has a built in CSV tabular editor and viewer was the best day.

Excel has that too. But you can't just double-click a CSV file to open it.