@npzman What you're saying in the case with Alien Force and Ultimate Alien sounds like a case of bad writing; especially in regards to Jimmy Jones. I am not a fan of how Ben's identity was publicly revealed by Jimmy. I thought that was a really dumb thing that Ultimate Alien did.
In the case with the Original Series, Ben's enemies don't know about his other family members. Who they are? What do they look like? Where they're at? Etc. Knowing Ben's identity wouldn't put his other family members in danger. Even then, the Tennyson family would certainly be an "off limits" thing here. We've seen what Ben (and Gwen) would do to anyone that dares to go after his family.
Also, I'm pretty sure that revealing Ben's identity to the public wouldn't really get in the way of him being a hero. He would still go out of his way to stop the bad guys and be a hero. Whatever obstacles do get in his way, Ben would just find a way around them...or not even care about them. Ultimate Alien, Omniverse, and the Ben 10,000 future showcased this. Revealing Ben's identity publicly did little to nothing to benefit the villains.
Along with protecting his family, another reason why Ben's hero identity was kept a secret for a while was so his family didn't know what Ben (and Gwen) were doing. The idea of two 10-year-olds using magic and the Omnitrix to be heroes, thus putting their lives in constant danger, wouldn't really sit well with Ben and Gwen's parents.