Red - A car should be warmed up in cold weather. Nobody bothers. The cars survive anyhow. Your motorcycle is substantially the same.
Air-cooled engines have more of a warm-up issue than water-cooled do. Overall the temperature control of an air-cooled engine is sloppier than a water-cooled, and so the machinery has to be built with more allowance for expansion/contraction. This CAN (not will) result in poor lubrication until the parts get warm & expand to their running sizes.
So as a general matter for bikes/cars from the 1970s & 1980s, warming an (air cooled) bike is more important than warming an equivalent technology (water cooled) car.
Your 2007 Vulcan is predominantly water cooled so that issue is immaterial. But it does affect a lot of “common sense” knowledge & writing on motorcycle web boards.
As to oil circulating, there is oil everywhere all the time. In any engine, car or motorcycle, it slowly drains from the top-most areas of the engine after shutdown. Those parts retain a thin coating of oil, not the thick cushion they normally have while running. It takes a few seconds, tops, for fresh oil to be pressurized up to the top of the engine after start. That fact is accounted for when they design these parts.
Another issue is oil viscosity. In cold (ie 30 degree F) weather, oil gets thicker. When the owners manul says “cold” they mean 30F or maybe -30F, not 50F like you have in the Bay Area overnight.
If the oil somebody has installed is for much hotter weather than they operate the bike in, it’ll drain off after shutdown but then be thick & gooey in the crankcase the next morning. So if they start it up when it’s 30F out & immediately (ie within a few seconds) red-line it, there may be little good free-flowing oil circulating yet. Under that scenario, some incremental damage might result. That is the disaster scenario the owner’s manual is trying to warn you away from.
I don’t think it has ever been cold enough in the Bay Area (at least since the last Ice Age), for you to have the slightest reason to be concerned about any of this.
Start the bike, put on your helmet & ride away. Accelerate sanely & obey speed limits for the first minute or two.
Start your car, put on your seatbelt, turn on the radio & drive away. Accelerate sanely & obey speed limits for the first minute or two.
Same warm-up requirement, same warm-up accomplished.
And as casdave said, if you are treating this machine like a delicate flower, you are at some risk of harming it. It is meant to survive mistreatment by crazy bastids. Just be less than moderately crazy & you’ll be operating well within the design envelope. And it’ll run great for another 100K miles, which is an eternity for a bike.
Relax dude, this is about fun, not worry.