One thing Yevtushenko says about himself in The Paris Review is that his poetry is an outpouring of emotion and emotional reaction to events.
"Alas, I myself belong to a less exalted poetic tradition. My verse is usually dictated by contemporary events, by sudden emotions—but such is the nature of my talent . . . when I am deeply moved, I am prompted to pour my feelings out at once in verse.” (Olga Carlisle, The Paris Review)
As a consequence, the themes that dominate his works will be related to contemporary events and to emotions. This poem was published in 1963 during what is known as the "Khrushchev Thaw" (mid 1950s to early 1960s) when hopes were high--though never realized--that artistic freedom might return to Russian and that poets could once again sing freely without constraint or restraint. As Olga Carlisle says, the hopes were disappointed and, in 1965, Russian artists and poets were feeling their disappointment:
In 1965, the prevailing mood in Russian intellectual circles is a mixture of impatience and fatigue.... (Olga Carlisle, The Paris Review)
Thus a social theme built on "contemporary events" might be stated something like this: Denial of the exercise of artistic freedom is a "city" of "frowning" "gloomy ballet" while full freedom is a "city" of "daisies" and "shining multicolored" opportunity; nonetheless, the restriction of "dejection" adds power to the emotional poet's song, so denial opens advantages that the poet can accept:
Better let me be tossed around--
To the end of my days,
The psychological themes that undergird the social theme are (1) the psychological perception and impact of negation, fear, and dejection versus (2) the psychological perception and impact of acceptance, a thrush's "song," and freedom from suspicion.
But in the town of Yes--
life’s like the song of a thrush.
This town’s without walls--
just like a nest.