you see DBs because people have added “public” to their database.
As for the error, it is stripping possible “malicious” code out, its a pain, and why I never recommend using the web based manager, I’d highly recommend using aqua data studio.
I don’t know, but they do, it is developers Security is the last thing on some developers minds. I know first hand from some requests we get. Others are very good and think about it, many simply don’t, until they are defaced.