Notably, it's potentially easier to hold large companies to account compared to a bunch of small ones equivalent in total size.
For example, bad news about Uber discourages people using Uber all over the world. Bad news about some taxi's behavior only discourages using taxis (or a particular taxi provider) for that one city, usually.
In other words, large companies are more susceptible to reputational threat, which is is why, for example, they tend to be more careful about what their employees say online. If an employee of a random 10-man startup says something racist online, that's nowhere near as big of a deal as if an identified Googler says something really racist online.
