The use of the term Scotch in the name was a pejorative meaning "stingy" in the 1920s and 1930s.
http://en.wikipedia.org/wiki/Scotch_Tape
[NB In the UK the equivalent product is sellotape].
It's true that Sellotape has become the generic name for adhesive tape, but Scotch tape is a well established product in it's own right in the UK market.
I was also surprised to see they didn't cover why it was called "Scotch" tape in the article as I find it pretty comical even though I'm also Scottish.
I've always known Scotch Tape to refer to Scotch Magic Tape, the slightly opaque, better-quality sellotape, rather than just generic sellotape. More expensive as well, so I always got told to use it carefully & in moderation when I was a kid. It has a little tartan-pattern strip of paper at the end of the roll so you can find it, I never really thought about why it was named beyond that.
> The bodyshop painter became frustrated with the sample masking tape and exclaimed, "Take this tape back to those Scotch bosses of yours and tell them to put more adhesive on it!" The name was soon applied to the entire line of 3M tapes.