Calland may well be biassed, that's fine, everybody is - it's literally impossible to be unbiassed and thus impossible to write unbiassed. And an opinion piece has even more leeway for bias than ordinary news.

But the part of the article under discussion - where many claim they 'stopped reading' was not biassed, because it wasn't expressing any opinion at all - it was merely stating simple, objective facts. 

I suspect they were more upset that the article strongly implied these facts were bad things, since it seems mister Coles is rather fond of homophobia and doesn't seem to like it being describe as something evil.