Your posts have been wild, but the last statement here is the biggest stretch of all.
There's a difference between actively eliminating a group of people, and that same group of people choosing not to have kids due to the requirements of "success" in their own culture.
Even though I don't agree with you in the slightest, I somewhat sympathize with you simply because I think you truly believe your perception is a reflection of reality as the saying goes. When it feels like the world is against you or apathetic towards you, that's a terrible thing.
Let me preface my point with this. I'm not white, but I am 'Western' culturally speaking. Unlike you seem to be able to do, I can acknowledge the flaw of western culture and still appreciate the positives like scientific and technological progress.
Ultimately, this is the truth of the matter. For centuries, Western European cultures have actively sought conquest of new frontiers with wealth and power being the two primary motivators. This set the stage for our modern trade network, technology, and capacity for migration.
The decision makers did not ask or care about the endgame of this activity, though. As wealth grew for the western world, it also grew for its average citizen, and like a drug, we have grown addicted to wealth.
White populations are in decline because they were one of the first groups to largely achieve the manifestation of the idea that "Anyone can be (financially) successful"
In the modern world, if your job doesn't pay you well enough, the only ways to maintain this success are to not have kids, have less kids or have kids later. You maintain this success culturally by making sure the few kids you do have know to follow the same line of reasoning.
Surely you aren't going to suggest that native non whites are forcefully suppressing white births? Or that immigrants are doing the same?
If you removed the immigrant or brown factor, you'd have the same situation as Japan with an aging population and no one to replace it.
The culture that led you to your current state, is also the culture that will be your undoing. I don't know what the solution is, but it's very clear that when financial success is the primary goal of individuals and infinite growth is the primary goal of governments and other institutions, population decline follows. Growth can always be greater, but the amount of time in a day grows ever shorter, and limits of human physical and mental stamina has a hard ceiling.