Well whupdeedo, that's informative.

Most of the people handing out this response about magick having no color only have a vague idea themselves what the term "black magick" actually means.  They tend to think that the terms "black magick" and "white magick" denote intent.  Under this misconception a harmful intent working would automatically qualify as "black magick".  (This is actually usually true, but not for the reasons they think)  Likewise, any beneficial magick working would automatically qualify as "white magick".  This is false.  Sadly, this is about as much information as you are likely to get from the majority of the pagan community when you ask about "black magick".

There are two main types of magick:   Theurgia and Goetia.

Theurgia, also known as "high magick" or "white magick" is magick designed to align the will of the mage with the higher will (godhead, universe, etc.).  The focus is on edifying the mage in a spiritual manner.

Goetia, also known as "practical magick", "low magick" or "black magick" is magick designed to impact the environment with the will of the mage; to affect wordly things for worldy purposes.

These are technical terms.  Classic "dark arts" magick such as evocation, sorcery, necromancy, cursing and various enchantments do fall under the "black magick" category, but not for their intent.  A spell to get a job would also fall under the "black magick" category, as would love spells, money spells, a spell to find lost objects or any other working aimed at a mundane result.

I think the reason most pagans don't bother to know this is they are mired in trying to avoid old Christian anti-witchcraft terminology and they mistakenly attribute the concept of "black magick" to that rhetoric.  The Greek terms predate Christian anti-witchcraft sentiments of the latter centuries.  "Goetia" happens to also be the title of one of the more infamous medieval grimoires.  An educated examination of this tome reveals a system designed for evocation of demons without compromising the alignment of the mage to the higher will.

The more ridiculous reason I've seen given is a sort of politically correct mindset determined not to use the word "black" with any negative connotation due to racial classifications.  This just further illustrates their ignorance as the use of the term "black" in reference to this category of magick comes from a belief that God is light and the absense of God is darkness.  It has nothing to do with skincolor or 20th century politics.