This is one topic that everyone will probably have a different opinion about, but here's mine.
To be a Pagan, you do NOT have to be a vegetarian OR vegan. They two are not related, really. There are plenty of non-Pagan vegetarians/vegans and plenty of non-vegetarian/vegan Pagans. Too many people rush into vegetarianism without learning enough about it first, and they end up in the hospital or something. I have a friend who ended up in the ER because of passing out because the friend in question wasn't getting all the things needed. It isn't JUST about protein, either. There are a lot of things that you have to be very careful about substituting with non-animal products.
A lot of Pagans are vegetarian or vegan, though. Some do it for health, some for moral reasons, and I'm sure there are other reasons as well. Personally, I WAS a vegetarian (and then a vegan for about a year) long before I "officially" declared myself a Pagan. I did it originally because a friend graphically described the slaughtering process to me when I was 13. After a while, it became more about my health, though. I have battled depression a lot, and being a vegetarian actually made it easier to deal with, and it helped with my PMS (which was HORRIBLE!), but I was careful with it. Now, I still consume animal products. Very little dairy and egg, though, because I'm mildly lactose intolerant and I just don't fix eggs often. I don't really eat chicken, beef, etc. very much, but I do eat fish. I'm basically a pesco-vegetarian, but I do eat some other animal products from time to time.
I've heard a few people say that becoming a vegetarian really doesn't help the animals (for those who do it because of the way animals are treated) because there are still tons more people eating them, than not. And, more than likely, for every person who becomes a vegetarian, there are probably several hundred babies born who will be eating meat very soon. The planet is very over-populated. A few thousand people cutting out meat isn't going to make a difference, really. I digress...
Yes, if you go by the Wiccan Rede it says to harm none. That's the reason a lot of Pagans give for becoming a vegetarian. But think about this: When people totally relied on their land to live, long before super markets and all that, what did they eat? They had harvests AND....? Yep, animals. They hunted game and used the whole animal, basically. Some hunters still do that today, but it's becoming less frequent since hunting seems to have mostly become a sport. In MY opinion, unless you set out with the intention of being malicious and causing pain/suffering/heartache/destruction, etc., you aren't really going against the Rede. I don't live by the Rede, but I believe that the line about not doing harm means doing it totally intentionally with malicious intent. Eating is survival. What you eat is your choice, though.
The point of this blog is that you need to THINK for YOURSELF about things, and not just blindly follow something. If you think you HAVE to become a vegetarian to be a Pagan, ask yourself WHY. Think about it, meditate about it, research it, THEN form your own conclusion about it. Don't just blindly jump into things because you think you should or have to.