OK, Wikipedia may not be a great source across the board, but you can find all the different theories from my link separately if you wish. All the links are in the admittedly long article for your convenience. The Wikipedia link gathers them together in this case.
"Often thought to be" requires a poll of all the people who might conceivably be affected. Does that mean one person has the thought often, or that several people have the thought? And if several, how many? Two? Three? Two hundred thousand?
What you're saying is that I am perfectly reasonable in calling you a racist, and because I call you a racist you are a racist, for using the name Jugurtha or even considering it, or thinking it's a great name with only positive associations, when it's clear to me that the name recalls the Irish Famine of the 1840s, no matter what your intentions are or by how long the name predates the Famine. I feel it's racist, therefore it is. Is that unreasonable? Is that in accord with the Race Relations Act? Yes and yes. It's been said on several occasions that there doesn't have to be any intent, but it still doesn't make "I'm being oppressed!" anything but ridiculous.
In what sense is trying to place the focus on the troll's actions misleading or unreasonable? It's not a diversion from the issue, it is the issue. It is vital to try to understand what the troll intended before jumping on your high horse and casually throwing the term racist around. In order to understand it is vital to look at the facts, and that requires attention to the troll's actions.
Fact: A troll vandalised the BNF extensively.
Fact: He did not just vandalise the Jugurtha entry, but many entries (see the MNHQ post further up the thread)
Fact: He used the term 'pissface' in the line for suggested nicknames.
And from that, you have deduced that the troll is a racist, a hater of the Berber people and their culture and history, who has incited children to bully Berber boys based on their ethnicity, that I and others am a racist if I don't think the troll is a racist, but an ignorant knob.