Because that's how markets work. If it is more profitable for them then it is for you, and it will be, they buy it from you. Such a deal is good of you (price is higher than what you would make) and good for them (price is lower than what they will make).
If I were you with your superior 'cryptographic' knowledge, I wouldn't waste another second in trying to break and fully de-anonymise a darksend transaction because that's what you've now staked your entire project's existence on.
Let me know when you've actually read what I wrote.