Tbh this may very well be related to the phenomenon that opinion polling on any given issue can be swayed to a large extent by how questions are phrased and biased by preceding question. Like I don't think it's either people changing their opinion, or people blindly siding with their "team". It's that many democrats don't have a strong opinion on fracking, and by affirming their current support for Biden prior to question on facking a subconscious bias was introduced.