Why does the ruling class promote discrimination?

[Questionable]

I've always wondered why the bourgeois needs promote viewpoints such as racism, sexism, homophobia, etc to the point of denying rights for these social groups. Sowing division amongst the working-class seems like a simplified explanation. Wouldn't it make more sense for them to promote the idea that we're all equal and should welcome everyone into society, thus giving them access to labor-power of minorities?

What does the bourgeois gain from discrimination?

[Vyacheslav Brolotov]

If the proletariat is divided, then it is harder for it to unite in order to overthrow capitalism and the bourgeoisie. Obviously, the bourgeoisie does not want to be overthrown. The bourgeoisie still takes advantage of minorities' labor, even if they do promote discrimination against them. A divided oppressed class keeps the oppressing class on the throne for much longer, as it has done for ruling classes throughout all of history.

[Psy]

If the proletariat is divided, then it is harder for them to unite to overthrow capitalism and the bourgeoisie. Obviously, the bourgeoisie does not want to be overthrown. The bourgeoisie still takes advantage of minorities' labor, even if they promote discrimination against them. A divided working class keeps the bourgeoisie on the throne for much longer, as it has done for ruling classes throughout history.
The problem is in a revolutionary situation the divided workers are still pulled into the revolution, take the Russian revolution of 1917 where Russia was rampant with discrimination of other Russians yet for the most part the discrimination of Tzarist Russia melted away.

[Vyacheslav Brolotov]

The problem is in a revolutionary situation the divided workers are still pulled into the revolution, take the Russian revolution of 1917 where Russia was rampant with discrimination of other Russians yet for the most part the discrimination of Tzarist Russia melted away.

True, but that is the kind of unity that the bourgeoisie thinks it can prevent, even though it really can't. It will try, though.

[Hermes]

However, if you take other examples the same is not true. The color line drawn by the ruling class of early colonial America fairly completely separated the riots that would emerge between the classes, making interracial class riots rare.

[Ocean Seal]

I've always wondered why the bourgeois needs promote viewpoints such as racism, sexism, homophobia, etc to the point of denying rights for these social groups. Sowing division amongst the working-class seems like a simplified explanation. Wouldn't it make more sense for them to promote the idea that we're all equal and should welcome everyone into society, thus giving them access to labor-power of minorities?

What does the bourgeois gain from discrimination?
They have everyone's labor power already. Discrimination or no discrimination.
Sowing the seeds of hatred between workers is not only a good way to keep them divided, but its also a good way for them to have an excuse when things are bad ie: Arab terrorists, Latino immigrants, lazy blacks, jews own everything etc.
Moreover, when things like wars happen, a bit of racism is always welcome. Paint all the Palestinians as terrorists and you have a whole generation of David Horowitz's at your disposal.

[Psy]

However, if you take other examples the same is not true. The color line drawn by the ruling class of early colonial America fairly completely separated the riots that would emerge between the classes, making interracial class riots rare.
The Great Railway strike of 1877 where black rail workers were drawn into the railway strike as revolutionary railway workers had stopped scabs by derailing trains thus blacks porters had no passenger trains to work on plus their workplace became a battlefield. Also there were reports of black and white railway workers becoming comrades in class struggle during the Great Railway Strike, I.E there is a story of a black worker in St Louis coming to a strike comity asking the striking workers "will you stand with us regardless of color?" And all the striking workers yelled back "We will!" in which St Louis ground to a complete halt till the US Army used bullets to terrorize workers back to work yet till then black and white workers were united under the goal of crushing their masters.

[Pretty Flaco]

If the proletariat is divided, then it is harder for it to unite in order to overthrow capitalism and the bourgeoisie. Obviously, the bourgeoisie does not want to be overthrown. The bourgeoisie still takes advantage of minorities' labor, even if they do promote discrimination against them. A divided oppressed class keeps the oppressing class on the throne for much longer, as it has done for ruling classes throughout all of history.

Yes. Because capitalists all come together and plot to divide working people. If capitalists are supporting anything it's probably because there's some money in it. It may be in the best interest in some to oppose racism and in the interests of others to support it, you can't say the entire capitalist class opposes or supports it.