It's not a safety feature. If it were, then all guns would be required to have them. Because that's what a safety feature is. It's an accessory. And an unnecessary one. It's optional. If it were a safety feature, then I wouldn't be against it being legal.
First, some places
do require them. Secondly, your reasoning is circular. You say it shouldn't be legal. You say if it were a safety feature it should be legal. You say that it's illegal, and therefore not a safety feature. You also argue that it isn't a safety feature because you wouldn't be against it if it were one. That's not a valid argument that it isn't one. It being optional isn't an argument that it isn't either, see more below. In no way are all safety features for well,
anything all mandatory.
I have to agree with you here - a silencer has nothing to do with safety.
Some people like to use them, and that's fine with me, but they are an unnecessary addition to a rifle and I suspect the proponents of them are either target shooters or rank amateurs (or both).
From a hunting perspective, anything that lengthens the weapon is a bloody nuisance and makes carrying the rifle more difficult. It is more likely to get caught on scrub and plants and no serious hunter is going to put himself in a position of stopping to screw the silencer on, so using them for hunting isn't an option.
The noise concern is a red herring. If it were a real safety issue, they would be compulsory in competitions, which they are not.
See above about being compulsory, but something being optional isn't evidence
at all that it isn't a safety feature. Slings are a safety feature, they are not mandatory. Manual and grip
safeties aren't mandatory, but if a safety isn't a safety feature, I don't know what is. Motorcycle helmets aren't mandatory everywhere, are they not a safety feature in PA? Motorcycle armor isn't mandatory anywhere (that I know of), and it is a safety feature. Floats in a pool are a safety feature, yet I don't see anyone but children swim in arm floats.
As for being inconvenient, yes, it can be. Like seat belts. Are they not safety features?
Noise complaints aren't a red herring in the least. Mufflers help protect hearing. In a competition environment, there are often
many other elements to help mitigate the noise risk, including range design, baffles, and of course how much easier it is to wear full sized ear covers over top of ear plugs compared to well, any other time. Even then, silencers help make things
more safe.