Hercules is Evil and makes innocents suffer
It's right in the opening narration, if your mind is sufficently open to the truth:Wherever there was evil, whenever an innocent would suffer, there would be Hercules!
Ares is Iphicles father
Iphicles and Ares look remarkably similar. Of course, Iphicles and Ares are played by the same actor in spite of the fact that they're supposedly not blood relatives (which, granted, isn't that unusual in this show). One possible explanation is that, in the Xena episode "The Furies" Xena suggested Ares had a habit of sneaking in to visiting warriors' wives while they're away at battle, basically pulling the same trick Zeus pulled with Hercules' mother. That may even be how Zeus first got interested in her. In terms of why Hercules father wouldn't notice his wife got pregnant when he was away, depending on when Ares came to her (e.g. a few days after he left) it might not have been clear from the timing that Iphicles wasn't his. "Two Men and a Baby" also mentioned that Ares had several children but he didn't care about any of them, Evander being the exception because of his powers. It seems reasonable to think at least some of Ares' children were half-gods (given he's obviously open to mating with mortals) and yet he didn't consider using them to challenge Hercules suggesting it's reasonably common for Ares to have children without god-like powers. So it seems at least plausible that Iphicles could have been Ares' son even though he didn't have any evident powers.