Simon Belmont is an asshole.
Really, think about it. Dracula is just trying to enjoy his nice, well adorned castle when some redneck, whip-toting asshole shows up, fucks up his entire place, steals and breaks all his expensive antiques (from candles to jewelry) and his money. Then some other asshole, usually a religious zealot, sets up shop to sell drugs straight out of his castle. How would you like it if some drug dealer broke into your house and started to sell crack out of your kitchen, while other assholes broke into your house and stole your valuables to pay for said crack?
So yeah, after all that, do you expect to bust into Dracula's bedroom and have him embrace you? No, he'd probably be pretty fucking pissed, hence the fireballs and molten rock things.
To add insult to injury, these hate mongers have a vendetta against things that don't look human. And even the ones that do they murder anyway. Most of Dracula's pets and creatures don't even attack you, or harm you, unless you touch them. That doesn't stop the Belmonts from launching a wholesale murder campaign on all kinds of endangered species for thousands of years.
The fact that we celebrate these backwater fucks as heroes is most perplexing, as it is Dracula that is being victimized by a family grudge that is passed down from generation to generation. The Belmonts never bring him to justice for his so-called "heinous crimes against humanity", and instead opt to dole out vilgilante, misplaced justice that is really more like terrorism than divine justice.
Fuck Simon Belmont.