Blinkered People

Newt made this statement of belief originally to Hogwarts Professor Prendergast, and the teacher seems to have been offended that Newt implied he was "blinkered" in thinking that a love of creatures was "strange," which is why he gave Newt a month's detention.

In making the statement again to Leta, adult Newt may be implying two things at once: people in general are too "blinkered" or blinded and therefore find creatures strange, or that people are too blinded by his affection for creatures so they find him strange and can't love him. For instance, Leta has chosen his brother and polar opposite Theseus the Auror as a love interest instead of himself. Or he may be thinking about his own love interest, Tina Goldstein, also an Auror and someone who finds his overwhelming love of creatures rather strange.