The video is clearly about the water block. They describe their experience while building a computer with it and then give purchasing advice. Sure seems close enough to a review that they should be fair to the manufacturer. And their ethics should not go out of the window just because the didn't put "review" in the title (when was the last time they did that anyway...).
That's really missing the point. They were trying to sell the water block to rich people with more money than sense that, importantly, wanted the best of the best. By not reviewing it correctly, LTT screwed a small company over pretty hard. Linus then went on to say that he made this decision to save $100 to $500. He was unwilling to spend that kind of money to preserve the journalistic integrity of the channel.
The fact that he tried to make it look like LMG was going to compensate them for the block (replying only after the GN video was released) only makes it worse.