Brother Love,
It seems that some rumors spread like wildfire, and this is one that caught a lot of peoples' interest. Be very careful what you pick up where, and check the source before repeating the tale. Rumors begin to take on a life of their own.
If you go to
http://www.margarine.org.uk/pg_app3.htm you can find the following explaination of a misunderstanding of terms:
Margarine is "plastic" at normal room temperature. The term "plastic" describes margarine’s ability to change shape when pressure is applied. For example, if you are spreading margarine straight from the refrigerator, you are applying pressure with a knife. The margarine can then be distributed over the slice of bread.
The plastic properties of a margarine or spread are determined by its formulation, manufacture and the temperature of the product when you are using it. The fat in margarine is mainly liquid oil but the oil is held in place by a network of small needle shaped fat crystals.
The rest of what you said about butter versus margarine is quite true.
Butter does burn easier so be careful when using it for cooking.