Is calling places to see if they have jobs considered rude?

Im a 20 yo who’s never had a job before (yes bad I know) and I haven’t been having much luck with online applications. Since i’m studying a bachelor of science I’ve been applying to pharmacy assistant jobs because I heard they prefer it if you have some scientific literacy. I’ve been calling some places to see if they’re hiring but the other end acted very irritated/rude. Someone flat out asked me how old i was then said ‘we’re looking for someone with EXPERIENCE’ in possibly the most condescending tone i’ve heard. I even had one person pretend not to hear me by repeatedly saying ‘Hello, this is [X] speaking’ without pausing to listen even once. (They only replied when I said ‘Can you hear me?’ in a very confused tone) I’ve had some that acted normal but this additude from some places made me wonder if this sort of thing pissess off employers, if I am doing anything disrespectful then I’d like to know.