Yes. In fact, the color on the Irish flag is described as Flannbhuí. oráiste is used by English speakers who learned Irish because that's how it's done in English.
As to why he's been downvoted, probably those same English speakers who want Irish to use words exactly like English.
I think it's worth knowing that flannbhuí (lit. blood-red yellow) exists -- it's the "official" word as used in such texts as Bunreacht na hÉireann / the Constitution of Ireland (†) -- but also that oráiste (after the name of the fruit) is far more commonly used.
† An bhratach trí dhath .i. uaine, bán, agus flannbhuí, an suaitheantas náisiúnta / The national flag is the tricolour of green, white and orange.
I was thinking along the same lines, Aya. I also checked to see if there was a separate word for the color orange vs. the fruit orange. (Thanks to Dim-ond-dysgwr for the explanation.)
Here are the words defined.