1) For Colorado: the measure on the 2018 ballot was to increase the distance that a fracking well could be located from 500 feet to 2500 feet from any homes / schools / major water sources. Would that "hurt" the industry? Slightly, but that would not kill the Colorado fracking industry.
2) Fracking is a multi-billion dollar industry. You can't kill that overnight. The leading democrats who declare that they are going to ban it would be committing political suicide if they actually enacted it. Fracking has created 1.7 million jobs. No president can survive putting that many people out of a job and expect to ever be reelected. Maybe I have more faith than you, but somebody will get in their ear and talk them out of it. It's the exact same thing as the green new deal. It's a lovely idea, but you'll notice that it was pretty much killed by the reasonable democrats.
3) Now, with all that said, I have no doubt that one of those candidates could enact legislation that would regulate fracking to a level that would make it unprofitable, thus giving it a slow death. You could enforce minimum distances like the Colorado failed proposal, enact minimum requirements for drill casing and protections, increase insurance payout requirements if any accidents happen....things of that nature. I could see those things happening, but a ban outright would be a disaster instantly.