The S word seems to have different meanings on opposite sides of the Atlantic Ocean.
There's a perfectly good explanation for that. It goes back to the days of the cold war. In those days, the "ennemy" was the Soviet Union. And of course, this totalitarian regime happened to be communist, which is a form a socialism pushed to an extreme. So, as is always the case in times of war (hot or cold), there were vast propaganda campains in the U.S. to "demonize" those "dirty evil commies".
The younger and most easily influenced generation of this era are today adults with families, and the effects of this brainwashing are still very much felt.
Note that, on the other side of the ocean, the same thing was going on, and today hatred towards those "capitalist pigs" is still very much prevalent among a certain generation in former soviet union countries.