Please accept that while I am no longer staff, I DO know what I am talking about. Additionally, while I am NOT an attorney nor is this my forum, I DO know of and HAVE seen legal action taken against such behavior.
Let's start at the basics.
1) ANYONE can copy and paste what they found on a website. In fact, the majority of your post is plagiarized from another site. Please do not try to pass these words off as your own knowledge, research and words.
2) The site OWNER gets to decide what stays and goes. As you know from reading the
Site Rules, the owner and Admin pretty much get to decide what stays and what goes. That is, they can allow whatever they want or don't want for whatever reason they want or don't want. The rules are all pretty clear on that....
Freedom of speech, another common argument soon follows this point, is not the case as it is a PRIVATELY owned and operated site. Just like I may allow you as a guest into my home, I may choose to tell you that you can't swear, put your feet up on my coffee table or kick my dog... my house, my rules. Likewise, HIS HOUSE, HIS RULES. Same concept. This isn't a "public" place where one can do as he likes.
3) Simply, the artist's music IS protected by copyright laws. This includes but is not limited to music, movies, books, etc. It is not public material, it is individually owned and said owner chose to share it with you. Just because they share it doesn't mean that it's yours to take. If they wanted you to download it, the artist would provide a link for you to get it for free. Copyright infringement is not taken lightly (example:
LINK shows a massive lawsuit over TWENTY FOUR songs from an unknown source).
4) YES, you CAN copy music, movies, etc that you own (note that this doesn't mean that you own the RIGHTS to it). These copies are for personal use only and cannot legally be distributed (as you mentioned). You, in the case of youtube, have not "purchased" the rights to anything and have chosen to copy it from someone who was letting you listen to it. Simply put, it's theft.
This is all part of the reason that the site owner and admin have taken the stance that they have on these items. Are they personally going to save the world from those who want to DL items, no. Are they going to be able to stop it, no. However they CAN put their foot down and say that they will not allow it REGARDLESS of it's legal (or illegal) merits.
Such behavior has ALWAYS been shutdown on this forum. I'm sure that, would you like to discuss it openly, there are plenty of other sites on the internet that will gladly discuss it with you and allow you to do it.