As a buyer, I've had reasonably good luck contacting sellers who were genuinely wanting to sell whatever it was they had listed. Specifically for vehicles, I narrow the parameters to "owner" "clean title" and "images". Anyone who can't post good pix and a good general description of their vehicle was quickly sorted to the garbage bin.
Back in February I bought a vehicle. Took me over two months of daily searching CL for suitable vehicles, literally thousands of ads viewed, only a handful of those were worthy of contact, and only a fraction of what was left warranted an in person inspection. I think I may have had a total of 10 vehicles I looked at in person. My personal favorites - NOT! - were the [censored] dealers listing as "owner" and not a dealer, misrepresenting the vehicle condition and history.
As a seller, good God almighty what drama! Probably had about a 60/40 split between genuine buyers and spammers. I can't even count how many times someone would go through the process of contacting, setting up an appointment to view said item, only to never show up, or worse, wasting my time with insulting low ball offers. My ads are always very detailed and include good quality pix. I do not have the ability to text, I have a land line or emails only. To avoid a plethora of spam, my ads specifically state to contact me by CL email with their phone number and I will call them asap. While this culls most of the spam, plenty still get through.
Moral of the story: CL, like Sleaz-Ebay, is a playground for trolls and scammers, and it is a PITA to have to sift through the garbage to find the gems. Half the battle is knowing how to search and knowing the warning signs of bad sellers/scammers.