This piece from the Atlantic will make you consider not to whom you're giving you're data, but with whom it may eventually reside. From the article:
If a...company can’t legally sell off its data, then it may just sell itself in order to cut its losses. Among the post-crash rubble, the principal value that a potential buyer might see in snapping up the company is its data. It’s like an acquisition hire, but for a huge and detailed dataset.
I agree that the best way to protect your personal data is not to provide it. More than once I've heard people offer justifications for providing personal data to a company simply because, they "trust them."
That's fantastic to have a service provider/company that you trust, but that rationalization presupposes the company and its policies are persistent. I'm not on every social media platform, but there's not one that didn't have at least one update to its privacy policy or terms of service. What's more likely is the company you're providing your data is aiming to be acquired by a larger company, whose privacy policies may not be in line with the original for which you signed up. And with most companies opting to collect as much data as possible and decide what to do with it later, at some point, your data could be in the hands of someone with whom you didn't intend to share it.