Steve released a video pointing out a bunch of technical errors and ethical concerns about how LMG is run, Linus just straight up admitted that he thinks it's unreasonable to have his fancy new multi-million dollar lab spend even $100 on retesting even though he absolutely knew that his results were inaccurate, doubled down after people started calling him out on it, whined that he didn't "sell" the one of a kind prototype that he'd promised to give back to the manufacturer, he "auctioned" it for charity, even though that had been explicitly stated in Steve's video, and then completely separately a former employee said that she had been sexually harassed while working there.
I'll help ya out since I felt the same way and spent too much time on something I don't really care about, though I do care for the person who was impacted.
They are a tech YouTube channel that tests components for computers and the like.
Basically, a former female employee (can't remember her name) who was the social media manager, made a post of her tenure there, and it was horrible. Sexual harassment, belittled, ridiculous standards for work. At one point she felt she needed to gash herself and go to the ER, just so she can take a day off because she was ridiculed for taking a sick day previously. There is whole shit ton more. I'd link the post but sorry I'm a little lazy rn.
The guy who is "de-friending" this Linus guy, is another YouTuber who does the same thing.
This was a hyper TL;DR, and I'm missing other things, but that's pretty much the jist of it.
He's the host of Gamer's Nexus, a YouTube channel that does extremely in depth and technical gaming hardware reviews, and occasionally also equally in depth and well researched videos about tech companies doing shady crap.
I feel like we are missing the most important context.
He basically lit the fire that started the whole debacle.
He is known for his investigative journalism as mentioned. And he is from the Youtube sphere like Linus and has done collaborations with him.
Steve however, turned his eye of Sauron on Linus this time and called out inaccuracies in his content due to a rush to meet timelines and a huge bungle on a small company's proprietary item.
This caused Linus to react badly and the community was pissed. Mud slinging started and an ex-employee's sudden revelation of the toxic culture of the workplace(still not verified), had started a massive shitshow.