Why people r so cruel??

That time of year thou mayst in me behold when yellow leaves, or none, or few do hang upon those boughs which shake against the cold, bare ruined choirs, where late the sweet birds sang in me thou sees the twilight of such day as after sunset fadeth in the west; which by and by black night doth take away, death's second self that seals up all in rest. in me thou seest the glowing of such fire that on the ashes of his youth doth lie, as the deathbed whereon it must expire, consumed with that which it was nourished by. this thou perceiv'st, which makes thy love more strong, to love that well, which thou must leave ere long. the first stanza compares the leafless limbs of a tree to a. yellow leaves b. sweet birds c. bare choirs d. summer

How does this passage contribute to the overall meaning of the story

2dogs and 2 humans how many people are there? animals are considered as people too?