Being able to Comment on someone's blog, is a privilege. The blog owner has worked hard to create his/her own little piece of journalistic wonder, and, if smart, will control what level of external input is allowed - mainly, the type of Comments.
Blogger controls that level of Comment, too, by supplying a way of categorising certain Comments as undesirable - or, SPAM. This classification suggests that, for one reason, or another, the blog owner deems the Comment to be undesirable1, and a breach of that privilege that he/she afforded you, as a Reader, in the first place.
What that suggests to me is, as Nitecruzr1 states;
"The bottom line here is that your style of comments just are not welcome, on these blogs."
So, why do we have Comments? What do bloggers want from Commenters?
Well, this is entirely subjective. I know what I would like to have from Commenters, and you know what you would like, I hope. I can only suggest what I would like. Anything other than what suits me, goes into the SPAM classification! That's right! Be nice, or be gone!
Here's some of the reasons I allow Comments on my blogs:
- To get feedback from my Readers - honest, clean, constructive, witty (if warranted), suggestive about my blog, or its content!
- Second reason - same as the first!
I don't want bloggers thinking that they can leave unintelligible nonsense on my blogs, or links to porn sites, or spammy commercial ads, or completely useless rubbishy, moronic, wastes of time, or 'space' observations - on my blog! I won't think for two seconds about ditching (marking as SPAM) that sort of comment if I see it!
I'm 100% sure that some bloggers do NOT have Comment Moderation in place, because they want Readers of all sorts, to leave Comments - as though there is a prize, or Ranking, for the greatest number of Comments! Like the old song says; "It ain't necessarily so"! The only 'prize', if you can call it that, is a blog-full of SPAM possibility. By allowing this gratuitous access for SPAMMERS, you are part of the problem!
I use Comment Moderation on my blogs, so I can vet the type of Comment. Don't think, either, that I only publish comments which put me in a good light. If the comment is critical, clean, and civil, it will still be published. That's not spam. It's constructive, and I will learn from it. Readers have to know that they can be critical, as well as constructive, in their opinion of a blog, or content.
But, they also have to know the boundaries for what is acceptable, and the SPAM Classifier, and your good judgement2, will assist.
1 - Who, Me? I don't Spam
2 - Which Queue is Your Comment in?