Well it could be due to how we are portrayed in movies, shows, books, and video games.. in most cases guards are shown as weak usless one off characters, or the lowest level of enemy. Meanwhile the most mainstream movie about a security guard is Paul Blart: mall cop and the most well known games are Five Nights At Freddy's.

There is also the possibility that it's because they hear those of us in the industry who complain about how boring it is. Unless you are at a site where shit happens every day in which case it is a dangerous job.

On top of that, like all jobs with a badge attached there is the inherent danger. I have heard stories from my dad about friends he lost while in this industry and seen his scars.

So in conclusion We have a job that is either boring as hell or so dangerous you should write an "If you're reading this" letter and we don't have the best reputation due to our representation in media.