You're new so you might wonder why you're downvoted. Hackernews has some guidelines, and while they're far from being perfect they do help to maintain above average online conversation. Please have a read (it's pretty short!): https://news.ycombinator.com/newsguidelines.html

Key point related to your comment:

> Be kind. Don't be snarky. Have curious conversation; don't cross-examine. Please don't fulminate. Please don't sneer, including at the rest of the community.

Sometimes arguing about where the line should be drawn necessitates establishing that there exists a line.

By mentioning child porn, he/she shows that there is actually a line and now we can discuss where it should lie.

Please make your substantive points without name-calling, which is against the site guidelines:

When disagreeing, please reply to the argument instead of calling names. "That is idiotic; 1 + 1 is 2, not 3" can be shortened to "1 + 1 is 2, not 3."

https://news.ycombinator.com/newsguidelines.html

Be careful. Your hot air may just blow over the straw man you’re arguing with.