There are some very good points and examples in a recent article about how Airbnb enables and permits discrimination on its hotel platform (and doesn’t care that it does).
One thing that I’ll add is that what tech could do for the hotel and taxi industries (but invariably never does) is establish platforms that make discrimination by all the parties involved much more difficult. Airbnb, as mentioned in the article, could hide the personal details of people making bookings. Uber could hide the identities of drivers and passengers until the ride has commenced, solving a problem that has plagued the taxi industry.
The fact that these platforms do not care about solving these problems eliminates one of the very few upsides of their presence in these markets.