What a question.. Of course it's spam.. you've been banned twice, enough reason to assume it's because of all the spam.
I submit 1 article... maybe 2 a day from my site. I get nervous for digging my site twice in one day...so far, no problems. Be careful, digg is too useful of a tool to get banned from.
The point is, why you submitted all you blogposts at once? You can divide it and submit it day by day, instead of spamming Digg.com!