They had it in game from the start.
It created a problem with queue times so they removed it.
Now it’s back in a very watered down form. You can only avoid 2 players at a time, and only for a week.
Being only able to avoid 2 at a time is a drop in the toxic Overwatch ocean. It’s nowhere near enough, especially on console where there seems to be a lot more throwers/trolls/smurfs/toxic players.
And you can almost be guaranteed that, for whatever reason you avoid someone, they’ll be doing that same thing a week later, so the duration needs to be permanent.