With centralized email providers there's always possibility for secret agendas. The fact their code is there for everyone to review it and the mindset of founders give me hipe they are legit.
Their blogging how to keep yourself private are not something 14 eyes would promote don't you think 🤔 I'm not an expert about Getman laws but they have robust digital rights in place for individuals and I'm not sure what Swiss have 🤷

The claims of that person are questionable and doesn't mean it's true. Nobody knows for sure. We can speculate about a lot of things and it will only be a waste of time.

Why not self hosting? Simply because I already have a ton shit to do and centralized services are there to save my time. Also my lack of knowledge how to set up super secured self hosted email is minimal. 

Even if they are a part of 14 eyes and are a honeypot, they are not looking for small fishes but for big whales and organized crimes. 

What they have on me? Absolutely othing and I bet their "allegedly" secret algos blocked me for being such a boring individual. 

I choose tuta mainly to avoid ad companies which is basically Google.