This whole, Google, is evil for hiring the authors of an app you like. Either they will put them to good use, or make less money.
This isn't as simple and one dimensional as calling a company "evil" - this is about the long term.
Startups in the valley are getting acquired earlier and earlier in their existence as google and Facebook and eventually overlap in their services and audience appeal.
The acquiring of the teams is defensive in that they take that team and their IP etc off the market from their competition. It is offensive in that it squashes any possibility that whatever service it was the startup had would compete for their similar service.
In cases like instagram, it was an obvious choice for Facebook as Facebook is the largest picture sharing service which also wraps all sorts of meta data around the users who are viewing those pics.
Thus, with instagrams reach it fractures attention from facebooks services/user. By acquiring them and ultimately layering the instagram features into facebooks pic offering the attention is not diverted from Facebook.
Attention is the resource that social services are harvesting from their users and monetizing.
If you're not looking at it from this perspective, then I don't believe your critically thinking about what it is that the Internet is, or how to build something that will last.
Companies that provide features, utility and services that keep the attention of users (especially when providing no physical product) are those that will have longevity.
So, capturing those that would build things that direct user attention away from your product is critical to these huge companies.
Im suggesting, that Google has the intent to maximize profits.
So, if turns out bad for us, as consumers, it turns out bad for Google.