Jewish people saying they aren’t Jewish

I have encountered many people throughout the past few years who are clearly ethnically jewish by descent, and know that they are, but shy away from saying that they are jewish, instead saying that they are kind of jewish or that one or both parents are jewish when they are asked. I’ve even had people be uncomfortable when I ask them if they are Jewish and that they are uncomfortable with being labeled as being jewish. What do you make of this?

Specifically, I am talking of people who don’t claim to be anything else instead (so not Catholics or Muslims) just like people without any identity at all including Judaism.