And then there's Cento

I agree plagarism is a pursuit not worthy of poets, however I did find this poetry form intriguing. It could be inferred as plagerism, why is it not?

The Cento form as described in PoutrySoup's Types of Poems:

Form:
Cento is a poetic form composed entirely of lines from other poems. Cento has evolved to include a patchwork poem composed of quotes or lines from other authors. The poet selects lines or passages from various sources and rearranges them to create a new and original work. The resulting cento poem often takes on a new meaning or conveys a different message from the sources. This form allows poets to engage in a unique form of intertextuality, drawing on poetry's rich tradition to create something fresh and innovative.

Examples:
"Cento Nuptialis," Decimus Magnus Ausonius
“Cento Between the Ending and the End,” Cameron Awkward-Rich
“She-Poets Cento,” Kate Daniels
“CENTO,” Sarah Gambito
Wolf Centos, Simone Muench
“Cento for the Night I Said, ‘I Love You,’” Nicole Sealey

Cento and Ethical Standards:
Since cento poems rely on using lines or passages from various sources, it's crucial for poets to be well-versed in copyright laws and permissions when creating their work. Additionally, it is essential to identify the original works of the individual lines. 

I will add that most of the example poems can be found at The Poetry Foundation.