https://en.wikipedia.org/wiki/Jim_Crow_laws
One of the major motivations in keeping Jim Crow laws was to prevent economic competition (a "race to the bottom") between whites and non-whites. See also FDR's pro-union/pro-white policies.
Also, the issue at hand for Airbnb is specifically about hosts discriminating against potential guests. How do hosts that discriminate against guests encourage a "race to the bottom"? There might be parallels between discrimination a la Jim Crow and discrimination a la Airbnb hosts, but they aren't in the form of economic concerns. Your snark about learning history seems misplaced.
[1] https://en.wikipedia.org/wiki/Plessy_v._Ferguson#Significanc...
Frondo is attempting to argue that market forces don't punish people (much) for discrimination. I'm simply pointing out that market forces weren't even allowed. People discriminated because the law said things like this:
"No colored barber shall serve as a barber [to] white women or girls."
"Any instructor who shall teach in any school, college or institution where members of the white and colored race are received and enrolled as pupils for instruction shall be deemed guilty of a misdemeanor..."
"No persons, firms, or corporations, who or which furnish meals to passengers at station restaurants or station eating houses, in times limited by common carriers of said passengers, shall furnish said meals to white and colored passengers in the same room, or at the same table, or at the same counter."
" Every person...operating...any public hall, theatre, opera house, motion picture show or any place of public entertainment or public assemblage which is attended by both white and colored persons, shall separate the white race and the colored race..."
http://www.ferris.edu/jimcrow/links/misclink/examples/homepa...
The remaining three are "separate but equal". We return to the question: what about these laws required that the "separate" facilities be of lesser quality? Nothing about "separate but equal" immediately screams "discrimination", but as we know from history, it can end in discriminatory practice. The de facto ramifications of the laws were that black populations suffered (economically/educationally/etc.) at the hands of white populations: the market forces were not strong enough to encourage a lifting of the laws, or genuinely equal facilities, as Frondo suggests. Similarly, market forces may not be strong enough to encourage Airbnb hosts to serve all potential customers equally.
Your causation is backwards: people created the laws (under guise of equality) because they wanted to discriminate (and, if you want to boil everything down to some ahistorical economic gesture, it resulted in market forces tilting in their favor). To say that the laws stemmed from the economic implications is a stretch, especially post Plessy.
Similarly, market forces may not be strong enough to encourage Airbnb hosts to serve all potential customers equally.
That may be true, but citing legally required discrimination as evidence in favor of that proposition is silly. No one claims market forces can fix bad politics.