People who criticize others annoy me, especially for such a silly reason!
For me M-mode is only useful in two cases:
1. When I use my TS lenses and want to shift. I meter before shifting then put it to Manual.
The reason is that shifting fools the exposure meter.
2. When shooting flash. I want to control speed and aperture. It's as simple as that. Flash is used in TTL mode with no ... annoying - pun not intended - preflashes and arbitrary selections of speed and/or aperture. I guess people who use E-TTL should annoy me but surprisingly they don't