What is a smurf account and why are they so controversial?

Smash pro Plup responds to controversy after “smurfing” in tournament - Dexerto

Replying to @Jack🦌 this alien Smurf cat meme is getting out of hand.

How to create a Smurf account in Mobile Legends

Smurf attack - Uncyclopedia, the content-free encyclopedia

What is the blue smurf cat on TikTok? Viral meme explained - Dexerto

Smurfs Kart PC Review

If that isn't the most obvious smurf account I have ever seen : r/apexlegends

Some smurf accounts are just so obvious that idk why they haven't get banned yet! : r/DotA2

Controversy as Smurfs beats Angry Birds as highest grossing iPhone game - CNET

Overwatch 2 dev begs players to stop smurfing

Is Riot even trying to deal with smurf's anymore? I understand smurf que is apparently a thing, but it's OBVIOUSLY not working. In 2 different games today I had a combined FOUR