The answer is simple.
Most of them are called flamers & they troll the net looking to create
emotional upheaval in people.
The best thing to do is to ignore them & not take them seriously.
The very basis of their rants is attention.
As for why anyone would spend time on Craigslist.
Well if they aren't there looking for a freak-show.
Usually it's to seek reputable local services.
Or perhaps to place a resume.
Or perhaps to shop, look for garage sales,or look in the free section.
No it does not make you more intelligent & wonderful if you avoid Craigslist.
Oh an on another note:
People will stalk & murder you in a shopping mall. or a cafe, or a bookstore.
People use the internet for kiddie-pron, & all kinds of bad things, but we're all still here.
Craigslist does not = murder.