I have to agree with the posters who have said you need to sit down with the barn staff and ensure that YOUR idea of inclement weather and the BM or BO know where your coming from.
Communication is key.
Also, not sure what their time line is regarding turn in, but just because you have come at x time, and he was still out... doesn't mean that your horse is staying out all night.
For us turn in can be anywhere from 4-6pm (winter months), and 4-10pm (summer months) depending on the weather, what has happened through out the day schedule wise (ie farrier, vet, hay deliveries etc).
So perhaps the times you came, they just weren't ready to bring him in.
And as long as he looks comfortable...even though it is raining he would e fine to stay out.
Now, if your horse is staying outside ALL the time and you're paying for stall board...then yes, you have something to complain about.
But I think the main thing in this situation, is to ensure that you and the BO are on the same page when it comes to interpretation of inclement weather.
Horses are like chips...you can never just have one