If you are saying that venture capitalists and naive investors are paying for part of my ride each time I take an Uber why wouldn’t I want to get as many subsidized rides in as I can before they go broke? How am I as a consumer not gaining every time this happens?
The idea is that while it is nice to enjoy subsidized rides at the moment, as a consumer you may suffer in the future due to Uber establishing a monopoly.
Uber has no moat, so cannot possibly exploit a monopoly. The hardest part of their service to replicate is the drivers, and since they're all contractors they are free to work for Uber's competitors!
Even if Uber gained 100% share of car rides in an area, if they decided to exploit that by increasing their prices it would be relatively easy to create a competing company and undercut them.
Uber can only compete on price, they have nothing novel that can't be replicated. Hard to imagine how they could control the supply in a meaningful way.
You are gaining as a consumer but many new retail investors in the stock or through ETFs may get burned when the business model stops working. Most of the shared economy startups are a house of cards expecting a magic bullet to solve their cost problem (self driving cars). The current stock holders are providing the hang time till that happens or not. The early investors will probably be all gone by then.
Your index fund is investing in a bad investment and you say the fault is that the bad investment exists? Why not choose a different fund?
We shouldn't put bubble wrap around everything in the hopes that no one can ever do anything that might harm themselves. This kind of mindset restricts the freedom of everybody.