Those who are attacking whiteness really just want to eliminate Christianity. For them, Christianity is the enemy and Western Christianity more so than anybody else.
Attlee was an atheist, but not an aggressive one
Some of the Labour tradition came out of the less strident Non-Conformist Churches. Always prolific sources of woolly-minded Christian Socialism.
But i think you are right that the biggest proponents of mass non-White immigration were always the atheists or (((others))).