There is posted on the internet what is said to be the police report of his statement, in which he admits he shot eight people of whom only one was armed, and six are now dead. So although he hasn't been convicted, it isn't unreasonable to assume that he did shoot eight people, killing six. Unless we believe that posted report is fake and the police and all the media are conspiring or unwitting participants in putting out a false story that the fellow in custody has admitted the shootings.
What he is saying about racial insults and being shot at may be true, but it is also consistent with the sort of muddying of the waters to be expected from the desperate when facing the legal consequences of their acts.
But even if he was subjected to intimidating posturing and angry words and even racial insults from his eventual victims, which is not impossible to believe, that wouldn't justify killing people, and his own account doesn't include him attempting to defuse the situation with an apology for trespass. (Even if I believed I wasn't trespassing, against so many people sure I was, I'd have gone along with them, apologised, withdrawn, checked the facts, and made a complaint to the authorities if I were proved right.) And if he was shot at first, once, as he claims, (and that part isn't at all easy to believe since subsequent actions he admits leave him in such a hopeless situation that he must try any excuse, however implausible), after shooting the one armed hunter any justification of self-defence would end with the opportunity to withdraw, and his hunting down and shooting seven unarmed people, (they were not all found within sight of each other, so the killer had to have pursued them separately) makes this clearly a case of a man giving free reign to his murderous anger, and whatever reasons understandably caused it to build up in him, there is nothing that can excuse acting it out.