It's mostly because it's from Russia, or some other eastern European country with different stuff than we have, the second tutorial linked to here is fine to watch with no attachments.  The one on Lovelytutorial isn't so much an attachment as software to view it, like Adobe Reader--having said that, some attachments or software or other downloads from that particular site (as well as others like it) may be hacked and full of malware and/or viruses, so you're better off not to download anything you don't really know the origin of.