Large companies don't hate you, they are simply (like "nature" or the universe) indifferent towards your well-being or continued existence... which is perfectly understandable, really. And, yes, this fact should really give pause to people who are thinking about basing an entire company around an API, portal or other service that is 100% controlled by a large company. Any such dependency should be seen as the huge risk factor that it is.

And while innocent bystanders do get whacked from time-to-time, I find that more often than not when big companies change their TOS in ways that impact other companies, there's actually a pretty decent reason behind the changes.

Facebook feeds got extremely spammy around the Zynga days, they are much better now (tolerable, at least, though still far from perfect). Not sure what your google story is, but I've heard lots of startup folks complain about changes google has made to their algorithms or TOS policies that hurt them only to visit their sites or look at their apps and see that they were actually pretty spammy and really deserved the deranking.