| Quote #1 I, too, dislike it. (line 1) |
The "too" here suggests that the speaker empathizes with another person, or group of people, who dislike poetry. The speaker isn't just spontaneously declaring her own opinion; she is responding to a prevailing opinion or feeling.
| Quote #2 Reading it, however, with a perfect contempt for it, one discovers (line 2) |
When the speaker began the first sentence with "I," she quickly added a "too" to indicate her membership in a larger group. In the second sentence, the speaker delays using any noun at all, leaving who is reading poetry and who has a perfect contempt for it ambiguous. When she finally introduces a noun, it is the impersonal and all-encompassing "one."