yeah.
just like all of the other nasty things people say they’re going to do in real life, right?
“Don’t call the cops, he might have threatened you ironically!”
I’ve seen Blizzard devs respond multiple times over the years that smurfing is not a problem because their SR system gets them to where they need to be quickly. That’s the only way they’ll respond to the issue. Apparently it doesn’t matter how many games they ruin over that “quick” time span. 
I guess my interpretation of Blizzard’s response was different. I took it to mean that they were working to analyze the behavior so they can catch people who smurf more easily. I have to imagine that something as anomalous as tanking 1,000+ SR should stick out like a sore thumb, and I believe the devs when they say they take these things seriously. They don’t want people like that in their game.
I see you’re new to the internet.
I really don’t think Blizzard does anything about it. I’ve reported a few of those groups over the last month or so, with next to no other reports for other things. Never got a " thank you action has been taken message". So I don’t think Blizzard cares about those groups. There is a throw to bronze group up every day when I play, almost 24/hrs a day.
Even when I can’t find any other kind of group in LFG, there is a throw to bronze. 6 stacking to throw in itself isn’t that bad imo. Depending on how they throw, if they at least give the enemy team a good fight so ti’s not a boring spawn kill or the like.
The real problem is once they fall down to Bronze, well then they smurf and ruin peoples. 6 stacking and throwing isn’t the big issue imo, it’s what they do with the rank loss after they throw.
Both, do the right think, block and move on.
This thread is why if you’re going to derank you probably shouldn’t throw as a 6 stack LFG but rather a soloQ because people will report group names they see if you make one.