First of all, you can't edit your main post after a while. This to me severely limits what thread posters can do and it enforces the embarrassment of spelling mistakes or incomprehensible texts on the thread maker. I often make threads that I check, check and re-check for spelling errors, but it's only days later that I find them, or days later I find out that a sentence doesn't make much sense in the way it's written.
Secondly, some threads people make contain personal information that they desperately want to be removed for whatever reason. Maybe they feel that they embarrassed themselves with what they wrote, maybe they were drunk. Whatever is the case, editing the main thread isn't enough because people often quote the main text. The whole thread would need to be deleted.
Yes, sure, you can request a moderator's assistance, but that feels like it's putting unnecessary pressure on the moderators and will result in annoyance, and what if the moderator "just doesn't feel like it"? You're stuck.
One of the bad things with Reddit is that the downvoting system instantly shuts up the poster and the crowd is always right. This isn't really a problem with this forum but the negative connotation of "red" on some votes/ratings and green on others is not necessary. They should be colorless, neutral. This way you also avoid potential conflicts.
