Polled each and every one of them, did you?
For the record, I don’t believe it because almost every Protestant/Evangelical/Pentecostal church is packed with former Catholics and of all the ones I’ve talked to about leaving, not one of them gave wanting a divorce as a reason.
Why should they? They can just get an annulment (aka. Catholic divorce) if they don’t like their marriage and stay in the Catholic church.
I have never met a “former Catholic” who attributed their loss of faith to theology or unfulfillment (though some Catholics complain about both); every “former Catholic” I know (who actually attends services anywhere else, as opposed to just becoming a non-Mass attending Catholic) did it over personal involvement with the divorce/remarriage question.
Here in NJ our former governor did it after leaving his Catholic wife & child; he went to an Episcopal seminary and moved in with his boyfriend.