A genocide is actually happening however you choose to spell it or sarcastically pronounce it. It’s a serious thing. Children are dying. Millions are becoming refugees. A mass famine is spreading. It’s a perfectly reasonable line to draw to not vote for someone enabling it, especially if it can possibly pressure that person to take a better actions to save their job. It doesn’t require bad faith arguments or fake troll bots. It requires actual humans with real morals and ethics appalled by what they are seeing and who actually believe “never again” means “never again”, especially when it’s something done by their government that their voice can possibly change.
He still has time to improve his stance, if it’s not for moral reasons or to save lives, I hope it eventually becomes to save his job and keep Trump out of office, though I’m not sure the movement will ever become big enough to affect his electoral chances with how much influence AIPAC has in our politics, and how much liberal Americans hate Trump more than genocide, so you can probably rest easy on that front.