It's a human factors issue and has been known about for decades. You live on a busy road with lorries/motorbikes etc. thundering past, and as you sit in the back garden, not being able to see the trucks/etc, you filter out that regular, been there for years, ground noise. You can't do anything about it.
As you sit in your back garden a jet rumbles over head. You look at it, focus your eyes & ears on it and think how noisy it is. You grab the phone and complain, because you can. The politicians are mambying to a small minority. Years ago, west of LGW, there was a known local, who sat in his garden with binoculars, db meter and telephone to hand. There are just the same sort at all major airports. Some have more clout than others, and a louder voice in the relevant ears, but it's the same science and same problem as else where. It's a NIMBY issue. This, oh my gawd, steeper approach shock horror BS is just that. It won't solve the root problem, if there is one. Let's first identify the real problem and then design a solution, not suck it and see trials. That's the politician's answer, not the scientists.
But perhaps that is what is really going on; a political fudge to be seen to be doing something and then hide behind the report that will take yonks to be published; yawn, but clever.