You cannot counter a Sturmtiger with tanks because guess what? It one shots anything! If you truly beleive that USF and Soviets have a similar unit to the Sturmtiger please point it out to everyone.
You can counter the sturmtiger with tanks. Flank, attack from different angles. Of course you will lose all your tanks, when you a- move them into a blob infront on the ST.
The ST neeeds time to aim and to shot. What are you doing if you see a ST?
OMFG a Sturmtiger. "pressing Alt+F4"?
I do not believe USF/soviets have a similar unit, but tools to fight.
btw you can use a democharge and a mine to get around 700 damage. "Close" to 1000