I agree as well. This is why others and myself have asked for clarification on the amount of "frost" from the OP. So we can clarify what or even if there was an issue.
Because, "frost" to me is just like the little frozen condensation left after fueling, anymore than that is "ice" IMO. But someone else might think of lots of actual ice obstructing flow and hence a severe safety issue.
Either way, listing and airline, and flight number on APC or any public forum may get this crew in trouble. It would have been better to say something like "on a regional jet yesterday, XXXXXX happened prior to takeoff, is this an issue?" and just see what people think about it.
No need to cause a panic, and possible damage this crews career over what is likely a misunderstanding by a passenger.