An insult and a slur are extremely different things.
https://www.merriam-webster.com/dictionary/slur
1a : an insulting or disparaging remark or innuendo
And to the point, in NYC media circles, it is nearly the equivalent of an actual slur which is why I called it that. Just one writers want to use as opposed to one they think it is inappropriate to use.
Because I'm sure that actual landlords don't have a problem being referred to as landlords, so you must be referring to some other group.