I dont know if its a bug, it makes navigation more simpler.
Any evidence to back up the claim?
When 10+ years ago I was moving from Linux to Windows, the case-sensitve file system was one of the major risk factors.
But even in the beginnng, I have encountered precisely zero problems with it. And I'm the type who works mostly on the terminal and should be directly impacted by the case-sensitive file names.
The thing is, these days, nobody types the filenames manually: it is either click in GUI with the mouse or filename completion on the command line. And even if the filenames needs to be typed manually, literally everybody universally uses the lower case. (That even on Windows. And I have helped in past correct the case handling in several Windows applications so that they create files with consistent upper/lower case names. Because users were complaining that it is inconvenient and kind of fugly that sometimes output filenames are upper case, sometimes lower case.)
As such, I consider case-insensitive file names to be a redundant feature.