Why are winter tires slippy at 62 degrees?

I am burning up my winter Pirellies because I hate them so much. I just passed inspection with them but the rears were at the absolute minimum for passing PA. So now, at 62 degrees and nearly worn out, they are slippery as all heck. I can break the back away just excellerating hard in a turn. Really beyond squirlly. I thought these winter tires may be extra sticky given their softer compounds are designed for colder tempuratures. What gives?

If they still had lots of tread, they'd likely feel even worse because the tread blocks would be squirming all over the place.