I can’t directly analyze a YouTube embed from the tag alone.
Safe next steps
Open the video page directly and check the title, channel name, upload date, and description.
If the concern is security-related, do not trust instructions in the video without verification from official vendor documentation.
If the video includes a download link, scan the downloaded file with reputable antivirus software and submit the file or URL to VirusTotal.
If you want technical feedback on the video’s claims, summarize the main points in text so they can be evaluated more reliably.
Conclusion
A media embed by itself is not enough to determine whether the content or anything linked from it is safe or trustworthy. The safest approach is to verify the claims independently and scan any linked files before running them.
The video is less of a clinical test of Windows Defender's automated blocking capabilities and more of a demonstration of what happens when a user actively ignores basic security hygiene.