That amount of rust looks fairly normal/common to me, especially on a Ruger. Ruger uses castings to make their parts and cast parts tend to rust easily. To remove the rust, use 000 or 0000 steel wool wetted with a good gun oil or CLP type product. Buff it out, wipe it all clean and re-oil heavily. Rust and wear issues around the forcing cone of a single action revolver is a very common complaint with all brands, including Ruger. The problem is that the forcing cone sees the most carbon, metal fouling and heat, but since the cylinder doesn't swing out easily like it does on a double action revolver, most people never clean the forcing cone. Because of this, you get mixture of carbon, lead, brass and who knows what else caked on the forcing cone. Mix even a tiny bit of moisture in there and viola, rust.....
To prevent further rust issues, always clean the forcing cone well and use a product that is known to be a very good rust preventer. Most who know me, know I use and recommend Corrosion-X. It is an equally impressive lubricant and rust preventative that basically makes metal rust proof when it is treated with it. I will go out on a limb and guess you weren't wiping that gun down with Corrosion-X, were you?

Especially on a revolver, corrosion protection is much more important than lubrication and EP/AW properties of your gun oil. A revolver does not need any type of extreme performance lubricant. They just do not create enough friction, heat or wear to need it.
I would not let something like this get you down or ruin your opinion of Ruger firearms. It is a fairly common, live and learn type of thing.