Why would someone feel the need to comment unpleasant things on sale posts

Hey everyone,

I’m new on the site and had come here after my father recently passed away to learn more about and downsize some of his vintage stereo equipment. So I posted the first item a couple days ago (way under the suggested price might I add) just trying to see if this might be a good forum for me to do this and within 24 hours, an idiot decides it’s necessary to write “Scam-o-llama” in the question box. This of course was then seen by about 30 other people before I had the chance to reply to it. My question is, why would someone here feel the need to do this. I’m not even sure what I did to deserve that kind of response. Hopefully someone can look at my listing and let me know what the hell I did to illicit that response. I get that I’m not super familiar but come on man!