In many, perhaps most, western democracies there almost invariably is at least one, and often several "workers'" political parties. Quite often at least one of them will have "workers" or "labor" in their official name to indicate this. Yet, in the modern world, it seems very rare that such parties actually promote the interests of the working class, who they supposedly represent. Too many times they pass laws and make decisions that harms the working class, and is protested by them.
But why? I have a theory.
Workers' parties usually start from within the working class, to represent their interests in parliament. They quite often tend to become very big parties because the working class is invariably by far the largest class in society, and thus they tend to vote for the party that promotes their interests the most. The representatives are from that same class themselves.
However, once the party becomes big enough, it usually means that the politicians and the parliamentarians start getting hefty salaries. They often stop being part of the working class, and become upper middle-class. Some of them even outright rich upper class (ie. "aristocrats").
Likewise as time passes and new politicians join the party, these new people might themselves not be working class at all, but middle-class already to begin with. Or even richer.
Even those who started as part of the poorer working class, now with hefty incomes, will move to the richer neighborhoods, where all the upper class is living.
Which, of course, means that these politicians are not surrounded by the everyday lives of the working class anymore. They are completely detached from the very people they are supposed to represent. Instead, they will be surrounded by rich people, the upper class, whose lives and needs are very, very different from that of the working class.
Don't get me wrong. In my view rich people can be rich. I have honestly and literally zero jealousy against them. I have absolutely nothing against them. Good for them, especially if they have earned it with their work and talent (but even if they have just inherited their riches, so be it; it's all ok in my books.)
What I am, however, trying to point out is that rich people, living in their rich neighborhoods, do not experience nor understand the struggles of the working class. The working class could just as well live on the other side of the planet, effectively, from their point of view.
And now, the politicians who are supposed to represent the working class in the government, are detached from that very class, and do not see nor experience what they do. It's no wonder that they become detached, and start acting against the interest of people they don't know nor understand. They only see the rich people around them, so it's logical that their thinking and attitude will be shaped accordingly.
If a certain ideology becomes popular among the rich people (such as virtue-signaling with immigration-friendly attitudes), the politicians will also likely share that ideology. Even if the working class doesn't. Thus the party that's supposed to represent them will act against their opinion.