It's an internally consistent view of the world. But it turns all the biblical events where humans appear to have agency into just silly scripted scenes, and it also turns the passion and self-sacrifice of Christ another scripted scene (with the Gethsemane episode thrown in for sadistic melodrama, apparently).
I'd say that (strict) Calvinism is the least Christian of the various sects that have attained mainstream success. Paradoxically, it produced some very sober and ultimately successful approaches to the earthly life.
If I can massively oversimplify, it's a theology where Jesus came to redeem only the Elect that God had already chosen to be saved while he had chosen to send everyone else to hell, so that the Elect could see His mercy (to them, not those poor bastards on the down escalator).
And, perseverance of the saints is the icing on the cake, because it came to mean that if you ever disagreed with your church or its elders, well, you obviously weren't one of the Elect at all, enjoy the hellfire.
So it's a great theology if you want to run a small, obviously better than everyone else, in-group of the Saved, vs. all the unsaved sinners God has already condemned.
To see how perverse it could become in the extremes, look at the role it played in apartheid.
To answer your question as well as I can from their perspective, the reformed understanding of pneumatic presence vs their understanding of the sacramental union and being forced to participate in the eucharist in that heretical way, would quite literally be grounds for leaving the continent.