Anyone can be a Game Master. The GM carries a heavier position than most other members. They are tasked with maintaining order, keeping the roleplay moving, and directing it down the proper path, plotwise. As such, they have executive authority over their RPs, and are expected to use it well. While they should not become tyrants, so long as they are acting fairly the staff will always support the decisions of the GM.
You are free to discuss things with the GM, try to persuade them towards what you think is right, give them ideas, etc. But do not argue with the GM. That will get you nowhere. If they've made a decision you don't like, live with it, and move on. You're a creative person. You should be able to handle these situations. The GM should be acting in the best interests of everybody, and if they're not, what are you doing in that RP anyways? You should probably go start your own.
If you truly think the GM is acting in an unfair and is harming the roleplay, and you can put together a good, solid case about it, contact one of the roleplay moderators. Otherwise, just live with it. It's probably not that big of a deal.
Other Related Links:
- How to Be a Good Game Master
- Steps in Creating a Roleplaying Game
- Roleplay Forum Etiquette
- Roleplay Abbreviations
- A Guide to Out of Character Discussion
- A Guide For Joining Roleplaying Games
- Recruiting For Roleplaying Games
- What Is Free Form Roleplaying?