Plagirism is inevitable, as you rightly quote Bloom, who I'm sure, in the spirit of his message, is quoting someone else - as I recall, it may have been Oscar Wilde, who characerised the writings of others in the minds of aspiring upstarts, as glowing petals to be plucked and collected in an assembled boquet of stolen ideas. But make no mistake, the difference lies between that knowing and unknowing distinction Bloom hints at - to fail in differentiating here is to snub the very sensibilities that the poetic instinct is heir to (at the risk of contradiction I confess, that was a rather bare faced pickpocketing of the great bard just there). We write poetry through our love of poetry. Let that love extend to poets I say, and let their credits be given where due.
Everyone could use Wilde's "talent borrows, genius steals" too. There is a non-subtle difference between inspiration and tearing the guts out of the work of another. F that. Many writers on here put their lives into their scribbles. I don't care if they are considered good, bad or indifferent poems, as long as they are an honest and truthful expressions of the writer. Anyway, social media sites are subject to same copyright laws as the real world. Solicitors won't be interested in any (however unlikely) aesthetic reasons.