Arena has no real matchmaking or has the trashier one (How-to piss off a community)
This speaks for itself.
This is an undoubtable example of how this game aims to build up frustration in you, hoping to trigger in your mind an "okay I'll start spending money to show you who's better" way of thinking.
Just a couple of matches before this one, I was complaining about the game putting me against people with 12k or more points and account power clearly higher than mine. Then the game basically told me "what? You're complaining about matches against 12k players? wait until you see this".
Sometimes I wonder, why am I still playing this for real ?