Hey
I'll do my best to answer specific questions.
1. Well, not every server has cross-server functionality, additionally, it matches based on ranked/match points as well.
You and that person might have very similar points, or just queuing up at the right time.
2. They might be negative or you're on a hot streak facing tougher opponents to climb.
3. Why would the community feel embarrassed? It's a successful team in arena, there's already people creating counteractive teams to face that.
It's the meta that has formed within the game, metas generally come and go after people figure out what to use against them.
As for the last segment, you started to shift from questions to a baseless opinion statement.
Anything that's remotely popular and successful, will be copied and built on, that's generally when a meta is formed.
Hopefully, that helped you understand a few things. If you have any more questions, feel free to message me,