You could argue the opposite: if you expose yourself indiscriminately to people who don't share your values, they'll have a better chance to change them. I think I operate under this assumption. Most people wear some kinds of masks in various situations, and I think some people who insist they shouldn't just lack basic skills in deception and lie detection. I'm not implying people are more malicious than some people expect, I'm implying deception is generally thought of as a lesser evil than some people think.

If we talk about really hacking your preferences on some deep level, I agree with the danger of unintentionally becoming someone else.