Welcome, good-faith commenters. You've taught me much.
Comments aren't just correspondence, but co-publishing. Therefore I reserve the right to decline to host a comment if doing so would make me feel bad. This is completely at my whim. A creative needs to feel good about his work in order to continue it.
This has nothing to do with fairness or freedom of speech. I must avoid the depression and obsession that ensues if I feel my work disrespects truth. I'm already overcritical of my work; graffiti makes me want to torch it.
I might decline a comment but respond to it with a post. I might be unwilling to host a comment that would be fine on my forum. I feel less responsibility for what's written by others on my forum than for what's approved as a comment under one of my posts.
I may decline to publish a long dissenting comment if I feel the position is unreasonable. In that case, I suggest making a short comment summarizing your position and then linking to your own platform. I feel less responsible for endorsing your position if fewer screen lines are devoted to it. Readers can judge for themselves quickly and move on.
If I do publish your comment, I may rebut it with a strong opinion, loosely held. Don't assume the certainty I assign to a statement. I am a probabilistic thinker who finds adding qualifications to a low-certainty position to be like adding bling to a low-value car. Antagonistically mistaking direct language for certainty is a quick way to earn my contempt. Direct language and clear thought are identical.
Moreso than probabalistic, I am an evolutionary thinker. Correct complex judgments are the product of error-corrected simpler opinions. Evolution is a messy business, red in tooth and claw, and I'm disinclined to stunt my intellectual growth by failing to match the ruthlessness of Mother Nature, the primordial bitch. The closer to my raw thought and further from polished publication, the more a contradictory commenter risks being exposed to the inhumanity of my mental ecosystem. A T3 blog is at most one step removed from raw thought.
Many incorrect positions have worthwhile truthful aspects. Just because I can't endorse your position doesn't mean I think it's worthless.
As for extended discussion, forums are better suited for that. Link to a change of venue before a thread becomes unwieldy.