Religion- noun

1.Belief in and reverence for a supernatural power or powers regarded as creator and governor of the universe.

Nope....many Wiccans don't believe this.....next.

2.A personal or institutionalized system grounded in such belief and worship.

Nope. Wiccans don't like institutions. Probably because so many belong in one. Besides, most of us have seen them cast a circle...you've got the guy in the east calling the Norse Gods....the chick in the West calling the Celts. Of course the guy in the south favours the Egyptians and the woman in the North is a Native American wannabe. So much for an institutionalised system. Next.

3.The life or condition of a person in a religious order.

Doesn't apply. Next.

4.A set of beliefs, values, and practices based on the teachings of a spiritual leader.

There seems to be one leader per 3 Wiccans. Hardly a unifying force.

5.A cause, principle, or activity pursued with zeal or conscientious devotion.

Hmmm....no place does it say that those who make up their beliefs to fit subjective situational ethics as they go along to be a religion. Bad Webster!

While Wiccans tend to be zealous, that does not a religion make. If you get 5 Wiccans in a room together then you tend to have 5 belief systems and each has their own idea about what is important and why.
This is hardly the stuff civilisations are grounded on or become stable with. There is no core set of beliefs. There is no unifying force save for the desire to do their own thing and society be damned. After all, freedom is what is important. Few, however, seem to remember that the consequence of freedom is responsibility.
The truth is much more alarming. You have a society that now favours subjective situational ethics over a moral foundation. The responses on the suspended student (student suspended because he claimed wearing full face paint as part of his being Wiccan, to school)bear that out. How dare anyone impose any restrictions of which I don't approve. How dare anyone challenge my personal notion of what is right.
So in pops Wicca. A series of belief systems that impose no norms. If you don't like one pseudo standard, just claim that your "path" doesn't follow it. There are no standards so no one is ever wrong. There is no set rituals or dogma. It's a make it up as you go belief. This is the perfect belief system for a group of people raised on social promotions, the destruction of gifted programs and honours days in schools so that no one feels bad. False self esteem is seen as more important than actually doing something to merit pride. Right and wrong are not absolutes. They are open for individual interpretation.
Rather than strive to achieve, lets make excuses for behaviour that is out of place in a pre-school. If someone says something you don't like....play the race-gender-religion card. Then tell them to shut up. But if someone tells you to shut up call the ACLU because your oh so enlightened rights have been violated.