zwoelffarben's summary is supremely good. I would like to add a few bullet points about the details that make this just so unbelievable to watch.
"Plagiarism" can cover a wide umbrella of pulling from sources without citation... This is in fact THE most egregious kind you're imaging. Verbatim, word-for-word reading out of articles written by small-time queer authors that James simply pretended were his own words, research, and opinions.
He stole the words of not one, but TWO different people who died of the AIDS epidemic. Stole their words and voices and gave none of it to their memory.
Nearly everything plagiarized was verbatim, save for a few intentional word-replacements: He would take "homosexual" and replace it with "queer". "Trans" and replace it with "LGBT".
He would occasionally skip over parts of articles while reading them verbatim if those parts were anecdotes that clearly did not belong to him, like one belonging to a trans writer talking about their trans experience.
He did, occasionally, interject his OWN few sentences... exclusively to include misogyny. In the middle of reading someone else's words about Ted Bundy, James interjects his own sentence about the "hordes of white women swooning over Bundy." He claims it's all "straight women" denying the gay rep in Yuri on Ice in the comment section of his YOI video. HBomb checked. There are no such comments. He has a "women have it easier" rant about ND Stevenson and Rebecca Sugar... who are transmasc and nonbinary respectively. (But hey, misgendering is cool if you don't respect their assigned gender right?) He repeatedly shits on the "straight woman" author of Love, Simon, despite her being bullied into coming out as bi due to exactly this, and when she gently asked him to stop deriding her as a straight woman fetishizing the gay experience, he continued to do it and acted like she'd blown up at him.
And maybe you're wondering "He copied so much verbatim. How did no one catch him?" They did. People did catch him. And he got them bullied into silence by claiming the people who noticed the plagiarism were sending death threats, were doxxing him, were anti-queer trolls, and were lying. The main person who caught him asked HBomb to keep her name out of the video and talk about her as little as possible due to the enormous harassment she'd been through.
He preached so much about being a voice for queer people, about how people needed to support him since he was doing this kind of work for queers no one else was... while stealing from, silencing, and squashing every small-time queer author doing the ACTUAL work that he lifted in order to fund his massively lucrative internet career.