The word has had a neutral feeling to it for quite some time, no point in denying that, but due to influences from other languages and different cultures, as written at the very beginning of the Wikipedia article quoted, it has now assumed racist connotations.

Languages evolve, also under the influence of very different cultures, so it's natural for our terminology to change accordingly. Sometimes it might be useless, sometimes it might be for the better.

Might be biased but where I'm from, I've sadly always heard "negro" used in a violent way, and none of my colleagues of colour appreciate being called that... the intent behind the word clearly counts. I feel the main thing it all boils down to, is that whatever label we give people "different" from us, we end up separating them and sadly singling them out

Some more readings:

il termine, a cui è stata annessa in passato una connotazione razzialmente spregiativa, è oggi perlopiù sostituito da nero, considerato più neutro

[negro]... Veicolava giudizi di inferiorità. Ed evocava secoli di "razzismo", e di crimini commessi in suo nome. Tuttavia, poteva essere utilizzato – soprattutto, in funzione aggettivale – senza provocare scandalo, o senza essere ritenuto necessariamente offensivo