Yeh, I can see how it can be disturbing to others; especially if they are doing mag dumps after mag dumps.
However, in my opinion (I may be wrong), for a defensive firearm, especially a mag-fed semi-auto, it can be a good idea to test trial, trying to rapid fire to test the reliability of a firearm, the magazine, and ammunition to see if it will malfunction or choke under repetitive load; running a drill at the very least.
I remember seeing a video by t-Rex arms where for a Kimber 1911 where when shooting under repetitive load; it would malfunction. Now, I have only shot someone else’s Kimber 1911, but it was at 1 shot per 3 seconds to hit the bullseye; so I haven’t had that malfunction before or enough experience with a Kimber 1911. I will include the video link at the bottom.
Based on my understanding, as a RSO at a range I frequent for VIP benefits, the one shot per however many seconds interval at some of the ranges are for safety and liability reasons because they know not all shooters are able to handle running a drill or mag dumping due to poor control and accuracy issues which could risk damage to range property; and is also there for people to improve their skills and accuracy by limiting the shots per second. We have a 1 shot per two seconds; general rule. However, we gauge control and accuracy, if they are shooting faster than that, if they are hitting the target, are not all over the place; then generally, I will not mind or say anything about it.
However, in my opinion, for ranges that have a 1 shot per 3-4 seconds rule; that is a little slow. In a defensive scenario, generally, that is not how it would play out.
Video of t-Rex arms Kimber 1911