All this is absolutely correct.
I want to abstract the basic idea of this even further:
It is never a good idea to judge thing A by only a single piece of its set of properties.
Example
Imagine, you bought a car. You think its mix of how it looks, performance during speeding up from 0 to 100 km/h, handling in left/right turns and its brake ability is a good fit for what you were looking for.
Now, imagine someone comes to you and tells you “your car is shit, it takes 3.3 seconds for it to reach 100 km/h speed, when starting from 0”. You would think, “wait, but the handling is pretty good, the braking is also fine, so I sacrifice these 0.4 seconds of speed increase for these 2 other performance properties”. Still, the other person again tells you “no, it’s shit, it takes 3.3 seconds to reach 100 km/h. My car takes 2.9 seconds to reach that.”. Perhaps that may be true, but looking at the other properties, this car has worse handling and far worse braking.
Therefore, neither car is “better” or “worse”; it depends on what you are looking for, what actually matters to you. After all, you are the one paying thousands of dollars for that car. It has to fit you, not some measurement, that almost says nothing about that car.
I think it is now clear to every human with at least average thinking capabilities, that judging – whatever it is – just by 1 single thing does not say anything about that thing.
It does not matter, if you are judging a car, a movie, a person, an animal, a painting or, in this case, an operating system. Everything that is not one-dimensional has always several properties it should be judged by. It would be absolutely stupid and narrow minded to judge it by only 1 single property.
Now, more to the topic and less abstract:
Taking more RAM is smart, if that RAM is available.
What is the point of owning a car, if you do not have a driver’s license?
What is the point of owning a hunting rifle, without having a hunter’s license?
What is the point of owning a painting, if you just store it in your basement, instead of showing it off in your room?
What is the point of buying a pizza, if you will let it go bad, so you wouldn’t ever eat it?
What is the point of having X GB RAM, if you only use half or a third of it?
If you have something, use it. If you do not use that thing, it is absolutely useless to you. You need to use it for it to fulfill its purpose.
Therefore, if you have 8GB RAM and you never go beyond 2GB RAM usage, then 6GB RAM (which can be expensive, especially when looking at laptop RAM) is totally wasted; you pretty much wasted your money on something you don’t even use.
So, it’s just a very smart move for software developers to use all resources available, if possible. This can improve responsiveness and the overall user experience of that software.
The only time you should worry about minimizing RAM usage is when you are running software on micro controllers or single board computers (though, even SBCs are becoming more lenient in this regard, especially so since the 8GB version of the newest Raspberry Pi 4 Model B was released).