I agree with your first explanation more than the second. I don’t believe the left is really demonizing or ridiculing Christianity that much. This is easily discredited by the fact that we just had a Democratic candidate, Pete Buttigieg, who was very open about his Christian faith and still attracted a good deal of support from the American left. President Obama was also fairly open about being a Christian and his general views on religion, yet the right still attacked him as if he were (at various times) an atheist, a Satanist, and a Muslim. The data I cite in the article is also pretty clear on which Christians mostly backed Trump and which ones did not.

What this all suggests is that the persecution conservative Christians in America say they are experiencing is rooted in an extremely narrow definition of Christianity. I’m sure many of them do believe Christianity is being demonized and mocked by liberals, but making this claim seem even remotely plausible requires that they ignore all other denominations and forms of Christianity but their own. Which is not only an arguably un-Christian thing to do, it’s also going to be a terribly unsuccessful way of persuading anyone to take their own particular brand of Christianity seriously.