A remote cold start doesn't necessarily mean extended idling. Some may do that, but I usually cold start from 20 ft away, once I get seated and belted, I am off. My truck will likely idle on about 30 seconds to 1 minute max before I start driving.
There are plenty of threads about RAM mpg in this forum, it's not BS, these trucks suck down fuel depending on several variables. The tire size and type, the type of driving you do, even elevation of the roads you drive have a big effect. A flat road versus one with lots of elevation changes can be night and day with mpg.
Most of the complaints come from Rebel owners, because the 1" lift, 33" Duratracs and 3.92 axles along with a window sticker EPA rating that is exactly the same as a regular street oriented RAM with street tires. You are allowed an exception by the EPA to adjust mpg down based on trim, which is what GM did with the Trail Boss, considering it had 32" Duratracs tires, they dropped the EPA rating by 2 mpg to be more accurate. FCA, however choose to not adjust the rating at all. People who aren't familiar with trucks were likely in for a shock, hence all these threads.
No one wants to brag about low mpg, these statements aren't fake, depending on your own variables, you can get close to the sticker or way off. I'm not complaining, I knew what I was getting into by being a truck owner for decades. I know that 33" A/Ts and a 3.92 axle ratio was not going to get me anywhere near the EPA rating on the sticker, which by the way was the same rating on a Laramie with street tires. That's what is BS here.