OK, I'll chime in.....
If you belong to a club they most likely have a standard set of rules and procedures for changing policy. I forget the name of the system but it's a standardized method. Most will have a two tier system, general membership meeings, and executive committee meetings. They create a lot of this crap in the Exec committee meetings but are supposed to present it to the general membership for approval.
Your reporting sounds like you don't go to those meetings. You abandoned your rights at that point. The old fudds in charge sold you out because they didn't even have to face your dissenting opinion. I know those god damned meetings are quite boring and I seldom (if ever) attend myself. I currently belong to two clubs and have belonged to 3 others. I was only really active in one.
We had some guys announcing rules that never went through the membership or even exec committee. Like one instance a club board member (trustee IIRC) decided on his own that my friend couldn't shoot his scoped hunting .44 magnum pistol on the 100 yards rifle range and must use the pistol range that was only 50 yards. No rule on the books, he just deciced it. It got straightened out in the next meeting but it was offensive to say the least.
Some of the restrictive policies are just plain wrong and some are in reaction to unknown persons maliciously shooting up target frames, cables, ceilings, etc. Most clubs I've belonged to don't have RO's unless there is a competition going on. It's self policing and sometimes people "play" around when no one else is around. like shooting their rifle at the plywood target numbers below the target.
The .50 cal thing can be something as basic as it's chewing up the backstop and they're worried about liability. I live in flat lands now and the berms are made up and not natural. Most clubs should have the berms improved but they generally are 8-15 tall. If that is the reason, hopefully it was discussed fully in the general membership meeting before being approved by the membership.
The battle over target shape is a spurious and obviously political one at best for the club. The second amendment isn't just for bullseye shooters or bench rest and they need to be reminded of that during your club's meetings. You need to tell them in no uncertain terms that rules like this are a cause for people to quit and go to other clubs.
I can remember some minor battles over rules at the aforementioned Watervliet Fish and Game. back in the 80's and 90's The involvement of younger members did help reverse some of the silliness you described. I don't know how many times some ole fudd would dare to say he didn't like my AR because no one needed them except for the mil. (meanwhile he wanted me to track down NM sights for m14's/garands at the state armory and five finger discount them for him
-big negative on that happening!) The second or third time, I jumped his ass (verbally) and didn't hold back one bit on how stupid views like that were divisive.
OK, that's my $0.03 worth.
Bottom line is I ask you to be involved in your club to make it be the club you want and need it to be.
SoS