i had a "buddy" that i was paired with in cozumel once. she was someone i never met. she lived on the island and apparently had a bunch of experience. once we hit the water, she took off and i never saw her again until i was back on the boat. nice.
I think your description encapsulates the genesis of why people get frustrated and in conflict. A typical scenario might unfold this way:
1.) Diver A is self-confident and doesn't want a buddy. He/she intends to dive along with the group and follow the guide.
2.) Boat staff in some places are determined everyone be assigned a buddy, maintaining at least the pretense all diving on their watch is buddy diving.
3.) Diver A suppresses an eye roll and knows arguing with these people is useless or worse.
4.) Boat staff assign Diver A and Diver B.
5.) Diver B has a more politically correct/'by the book' view of the buddy system.
6.) To Diver A, keeping quiet and playing along till they splash is simply a way to keep staff off his/her back.
7.) Diver A and Diver B each thinks his/her own view is right. Diver A can't risk expressing his/her viewpoint topside out of fear of running afoul of staff.
8.) Some people think Diver A is then obligated to dive according to Diver B's view. Diver A has other ideas and...well, it may play out like what you describe.
In fairness, not all dive op.s try to impose buddy pairing. Some destinations are even known for the attitude that you're a certified adult diver, and if you want a buddy, work it out; the op. is not a matchmaker. I think destinations that cater to a lot of local divers, particularly seasoned divers, are more likely to have that attitude. Those who hand-hold a lot of occasional dive tourists, not so much.