I wouldn't call it hypocrisy, more like having to deal with the unintended consequences of your action.
He and others that have come out to publicly criticize Facebook knew what they were building, they just didn't see how powerful Facebook would eventually become in programming people en masse. The way the last election turned out was the wake up call.
Sean Parker himself admits as much in an interview with Axios:
"When Facebook was getting going, I had these people who would come up to me and they would say, 'I'm not on social media.' And I would say, 'OK. You know, you will be.' And then they would say, 'No, no, no. I value my real-life interactions. I value the moment. I value presence. I value intimacy.' And I would say, ... 'We'll get you eventually.'""I don't know if I really understood the consequences of what I was saying, because [of] the unintended consequences of a network when it grows to a billion or 2 billion people and ... it literally changes your relationship with society, with each other ... It probably interferes with productivity in weird ways. God only knows what it's doing to our children's brains."
"The thought process that went into building these applications, Facebook being the first of them, ... was all about: 'How do we consume as much of your time and conscious attention as possible?'""And that means that we need to sort of give you a little dopamine hit every once in a while, because someone liked or commented on a photo or a post or whatever. And that's going to get you to contribute more content, and that's going to get you ... more likes and comments."
"It's a social-validation feedback loop ... exactly the kind of thing that a hacker like myself would come up with, because you're exploiting a vulnerability in human psychology.""The inventors, creators — it's me, it's Mark [Zuckerberg], it's Kevin Systrom on Instagram, it's all of these people — understood this consciously. And we did it anyway."
[0] https://www.axios.com/sean-parker-unloads-on-facebook-god-on...