Yeah, but being a powerhouse doesn't mean they don't introduce silly bugs. They do. E.g. on Facebook, a year or two ago, you could use dev tools and change hidden input field's value when writing a post and post to anyone's timeline (this story got tons of coverage for a bunch of reasons, vulnerability itself not being the prime one). Does it seem like a silly bug? Definitely. But it happened, it's not the first one, not the last one.

So it's a bit naive to assume devs at popular companies don't make bugs, they are superhumans, etc :)