Reproaches won't have any positive influence on what all of us want, a great atmosphere.
You should avoid a discussion about "the better supporter". It's useless and dangerous.
Atmosphere is easy to join in, but difficult to get started.
As
@Manchester33 said, it's about getting the "masses" to sing.
So you have to combine forces. Stand together, or sit together and stand up. You have to stand up, that's obvious.
Sitting is a passive body language. If you want to have a go you have to stand up. Do you?
You need easy and repeatable chants and shouts.
Not too exhaustive, thinking about the aging fanbase.
To spread your chants, try to upload high quality videos on YT
including lyrics and also on Bluemoon of course!
There are some already, but some songs (Posh Spice e.g.) are a no go, others are of poor quality or not up to date.
IF you have a critical/chain-reacting mass loud enough, you can start addressing other stands (or other parts of your own stand first!) to simply repeat your shouts or chants as kind of alternate singing, to involve more people. It's fun.
They'll get a booo until they respond and be rewarded by a big YEAH and/or applause.
Don't stop trying until it gets going!! It works.
Most important is, combine your forces.
Then more and more people will join in.