If someone's argument, and therefore position, is irrational, how can we trust them to give honest and accurate criticism of other arguments?
At which point you are completely forsaking your original argument (rightfully or wrongly, which is a separate concern), which is the idea of my critical comment above. It's unclear what you are arguing about, if your conclusion is equivalent to a much simpler premise that you have to assume independently of the argument. This sounds like rationalization (again, no matter whether the conclusion-advice-heuristic is correct or not).
OK, let me break it down.
I take "life experience" to mean a haphazard collection of anecdotes.
Claims from haphazardly collected anecdotes do not constitute legitimate evidence, though I concede those claims do often have positive correlations with true facts.
As such, relying on "life experience" is not rational. The point about condescension is tangential. The whole rhetorical technique is frustrating, because there is no way to move on from it. If "life experience" were legitimate evidence for the claim, the argument would...
And happy new year to everyone.