comment on " what man has made of man " in the poem " lines written in early spring " by William Wordsworth

In Wordsworth's "Lines Written In Early Spring," most of the poem is focused on natural phenomena. The narrator begins "in a grove," surrounded by birds, flowers, and plants, and he finds peace and joy in their presence. He explicitly states "That there was pleasure there," and he indirectly reiterates that joyous mood by describing birds that "hopped and played," flowers that "[enjoy] the air," and "a thousand blended notes" of the world around him.
However, the narrator twice repeats the phrase "What man has made of man." In both cases, the reference is prefaced by a line indicating sadness—the first time, "And much it grieved my heart to think"; the second, "Have I not reason to lament."
To fully understand the reason behind the narrator's rueful tone, we need to look at the entirety of the final verse:

And I must think, do all I can,
That there was pleasure there.
If this belief from heaven be sent,
If such be Nature's holy plan,
Have I not reason to lament
What man has made of man?

The narrator believes that the pleasure he takes from Nature (capitalized and personified) is part of a "holy plan." But this understanding brings him sadness. Since the plan itself is clearly a good thing, we can infer that he thinks the plan will not succeed. The narrator's sadness stems from his belief that mankind has collectively rejected the "holy plan," preventing itself from fully appreciating the joy that currently enraptures the narrator. With this context, one can understand that "What man has made of man" refers to modern civilization, society, and/or technology—those things that hold us back from appreciating the natural beauty of the world around us.