Vegetarian Confusion

I went to the Midwest Grill on Route 1 recently. My partner loves these Brazilian grills and I usually tag along for rice and plantains. Imagine my surprise when the menu says they offer a vegetarian plate from the kitchen, awesome! So our server comes over, explains the process and starts to take our drink orders - two large glasses of fresh mango juice. I begin to order the vegetarian option and she repeats "seafood and vegetarian plate," ummm, no, just the vegetarian plate. She argues with me that seafood *is* vegetarian, at least according to their menu. After going in circles a few times I finally explain that I get violently ill if I consume ANY animal products. Okay, okay, she understands, but they don't have a vegetarian plate without meat. Ugh! I browse the buffet - they do have rice, and plantains, I go for the buffet instead.

In the last week I've had four instances of vegetarian confusion. It goes like this:
Me: I'm a vegetarian
Them: Oh, but fish is okay, right?
Me: Nope, can't eat fish
Them: Hmmm, what about tuna?
Me: No meat, at all
Them: Do you eat chicken?
Me: No

What is a vegetarian you might ask? Well, a vegetarian, is someone who does not consume any fish, meat, poultry or animal byproducts. So, if I am a vegetarian why do people assume I eat fish or poultry? I may be more confused about it than they are.