No, and none of my friends or acquaintances hide their rock climbing, soccer leagues, BJJ, whatever. I mean it's definitely not the first thing I bring up about myself, but it's no secret. I cannot imagine that anyone cares, and anyone who would care is probably a jackass.
Once again, some people tend to think that others are thinking about them more often than they actually are. The truth is no one of these relative strangers cares that about you in the first place, much less about your hobbies.