Smurfs are ruining so many competitive games

After the last sale on Overwatch there has been a lot more smurfs ruining the games. And I mean a lot, every game seems to have 2-3 smurfs on average. Last game I played had five smurfs, four on the red team. And it really feels like a curse, those tryharding smurfs playing their main heroes are usually on the red team, blue team gets those lvl 20 attacks Torbjörns.

This is really becoming a problem when higher tier players are basically just playing their placement matches every season, then ruining matches in lower tiers with their smurfs.

Why isn't Blizzard doing anything?