And the reason they are now leaving the church is because the church has decided to once again embrace its core values, in the face of those who would destroy the church by compromising its values. Like garlic to a vampire, if they could not make the church change its beliefs to those of vampiric leftist liberalism, they want nothing to do with the church.
IMO what you describe is no doubt happening. But if that is so, then that means the Catholic church has been far, far smaller than the US bishops have been reporting for decades. Perhaps as small as five million Catholics total.
Everything is a matter of degrees. For example, it cites the attendance at mass weekly and political conservatism for the lower number, but both of those are problematic.
For example, just offhandedly mentioning Hispanics again, I saw a huge turnout in a church in Phoenix when the Latin mass was reintroduced. There were many serious Catholics there that likely hadn’t been to mass since a time after Vatican II, and the first few pews were reserved for the very elderly and invalid who were desperate to attend a Latin mass before they died.
As far as political conservatism goes, the bishops themselves have put out a lot of liberalism in past, so conservatism across the board is not a good discriminator for real Catholics, either. More like “core value” Catholicism instead of conservatism.
But this is on the “more Catholic” side of the scale. On the “less Catholic” side there is an enormous number who are not “fully” Catholic, to who are not really Catholics, but call themselves Catholic anyway. Remember it is only recently that the church finally had enough of the fake Catholics in positions of power, and the fakes had to go strongly anti-Catholic for the church to finally disavow them.