Hum. I think that might be ok, since when you embed the video on the post, the creator get the ad revenue, and If he want to, he may forbide embedding through YouTube.

But, If you download the video, post on your Channel, then post here that IS a problem. That is stealing.(also YouTube have Copyright detection mechanisms)

That is the big issues with text. If you copy(without authorization), people read what you copy, and two things happen:

1 they miss the source, and think you wrote It
2 people see the source but since already read the text, dont Go to the source.

Both ways the author dont get paid for his work, and someone not related profit from his brains.

If you wanna talk about this great article, say what you think about It, and link the source. This is How It must work. (Unless, of course, the author authorize Full reproduction)