If someone tells me that the fiction I'm creating in my RPGing is improbable nonsense, I assume that they mean what they say.
Conversely, if someone does not think that there is anyone who is producing improbable nonsense, then why even mention that possibility?
If a piece of fiction regularly relies on extreme coincidence on a regular basis, it isn't for me. A lot of people like types of fiction I don't, it's not an insult to acknowledge that.
P.S. I have never used the words "improbable nonsense".