If you look at your word without the 's' you'll see it looks the same as a particular slur. An automated internet filter might have struck it out without taking into account that the word you used is a completely different word with a very different meaning.

Back in like 2005 I used to go on runescape which was notorious for having an over-active swear filter, and was known to asterisk out things like 'hello' for containing 'hell'. etc.