Strangely enough I did have an opponent in automatch recently who tried really hard to do this with an M10, as their kind of 'opening play' rushing it before any other vehicle. Needless to say, it didn't work very well.
If Rumartinez says it got heavily nerfed in the past perhaps it makes a bit more sense. Possibly someone who hadn't played the game in a long time? It was weird.
From april 2017
M10
We find that the M10, which is a highly cost-efficient tank hunter is overperforming with respect to how it deals with infantry due to its potency to crush squads. Therefore, we are taking steps to remedy this, without, however, affecting M10’s mobility.
Chassis rotation rate reduced from 38 to 32
Turret rotation rate increased from 30 to 36 to compensate
It was a really weird Tank destroyer as it was made for flanking but it’s turret rotation was straight ass. So to win matchups you had to spam and blob so enemy tank would get stuck and your turret could finally turn around and kill it.
My guess is the player probably tried to drive straight thru your squad instead of turn over top of them. That was the trick, back then a small change in direction would initiate the crush and since they turned so quickly opponent had no chance to react.
Reading thru some of the old balance changes you can kind of see why certain units struggle. Penals/Rifleman got some heavy nerfs that were partially reversed for specifically Wehrmacht infantry scaling.