This seems highly irregular, based on my own experience.
In fact, I find myself creating a party of one lately, just so I don't have to manually mute their mics all the time. Sometimes, I'd just rather not hear them.
Good mic users are more rare though... I can agree on that. But there has definitely been more than I can count on my fingers and toes. Maybe it's your region?
It seems to be a big issue in EU on all games.