OP, great quote, well done getting into the mind of your character. I think you nailed it.
But anon at >>12204808 raises a fine point. Unless the Librarians in the party are close friends IRL, they might get the misconception that you're just being a dick because your RP can justify it.
My humble suggestion is to keep those prejudices, but be really sincere about them. Like someone born & raised in a very racist part of America that just went through sensitivity training, making a genuine attempt to being nice to "colored folks" because he's a decent person at heart, but failing nobly. The result - you come off as just sincerely RPing your character, yet your character seems even more prejudiced against psykers.
Example quote: "Brother, despite your daemon-possessed blood, know that I am proud to fight by your side. You have proven that those that bear the witch-curse can rise above their limitations and still serve the Emperor! And rest assured, Brother, should you ever be overcome by the warp-taint within you, mine shall be the sword that ends your suffering."