Lorraine dislikes going to the zoo because it makes her sad to see "all those animals and birds and fish behind bars and glass just so a lot of people can stare at them". She is most likely imagining herself in their place, and she knows that she would not like being confined like that, and that she certainly would not want a lot of people just watching her all day.
Lorraine particularly hates going to the Baron Park Zoo. She thinks the attendants there are "not intelligent". Lorraine remembers that she was especially annoyed a few years ago when she witnessed the way an attendant fed the sea lions. He "climbed up on the big diving platform in the middle of the pool and unimaginatively just dropped the fish into the water". To Lorraine, his manner and nonchalant attitude in feeding the sea lions was crude and insensitive. She could just imagine the poor sea lions saying, "Don't dump the fish in...pick the fish up one by one and throw them into the air so we can chase after them...throw the fish in different parts of the tank...let's have fun!" (Chapter 6).
Lorraine is a sensitive individual, and she is not afraid to voice her opinion when she thinks that something is not the way it should be. She believes that the animals at the zoo should be treated more humanely, and it angers and frustrates her to see that they are not.