You were warned by XLinkBot after you began adding greater quantities of links to YouTube. The bot doesn't warn or take action against the first few links you add, as naturally people do add links to articles they edit, but both Wikipedia and the bot records you adding links and once you exceed a threshold, you are warned after each link is added (that's why some of your edits have the Edit notice "Tag: repeated addition of external links by non-autoconfirmed user") and that's why there are five warning notices from XLinkBot on your userpage. This was upto and including a warning that you would be blocked without further warning (so no question of "ban first, ask questions later". Why didn't you ask for assistance before that ?