To understand the pit bull reference, read my post about pit bulls vs. puppies that focuses on extreme personality types in the work environment.
Many of us have had a work day where we are facing a major problem. We stayed up all night trying to fix the problem and we are tired, grumpy, or even downright nasty. We go into a standing meeting and vent. We might even talk about how we should have seen the problem coming months ago and shouldn't find ourselves in this situation. Grumble, grumble, GRUMBLE.
You are asking for help. You are attempting to point out a problem. You are calling attention to a cause that should rally the troops. Is your current attitude the best way to achieve this goal?
We all do it. Take a breath. Point out that you were venting and apologize. Start over on the topic.
If you want to solve a problem, it is important that you communicate things in a way that empower people to help you. Don't create a situation where they leave you alone for the day.
If you are the leader in the group, speak up. Don't let the temporary pit bull deflate the team's energy for the day. Protect the team, and provide the disgruntled support. They aren't grumbling for nothing. Remember, it is a frustrated cry for help.